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Abstract:

An integrated catheter placement system for accurately placing a catheter
within a patient's vasculature is disclosed. In one embodiment, the
integrated system comprises a system console, a tip location sensor unit
for temporary placement on the patient's chest, and an ultrasound probe.
The tip location sensor senses a field produced by a stylet disposed in a
lumen of the catheter when the catheter is disposed in the vasculature.
The ultrasound probe ultrasonically images a portion of the vasculature
prior to introduction of the catheter. ECG signal-based catheter tip
guidance is included to enable guidance of the catheter tip to a desired
position with respect to a node of the patient's heart. The stylet
includes an electromagnetic coil that can be operably connected to the
sensor unit and/or console through a sterile barrier without compromising
the barrier. The stylet can also be wirelessly connected to the sensor
unit and/or console.

Claims:

1. A locator for locating a portion of a medical device within a body of a
patient, comprising:a radiating element included with the medical device,
the radiating element capable of producing an electromagnetic field;
andan external sensor unit capable of detecting the electromagnetic field
of the radiating element after placement of the medical device at least
partially within the body of the patient, the external sensor unit
operably connectable to the radiating element through a sterile barrier
without compromising the sterile barrier.

2. The locator as defined in claim 1, wherein the radiating element is
included with a stylet that is positionable in a lumen of a catheter, and
wherein the sensor unit is positionable on a chest portion of the
patient.

3. The locator as defined in claim 2, wherein the stylet further includes
a first connector disposed at a proximal end thereof, wherein the sensor
unit includes a second connector, and wherein the first and second
connectors are operably connectable through a physical barrier that
provides at least a portion of a sterile barrier.

4. The locator as defined in claim 3, wherein the first and second
connectors are connectable so as to not compromise the sterile barrier,
and wherein one of the first and second connectors includes a piercing
component that pierces the physical barrier.

5. The locator as defined in claim 4, wherein the piercing component
includes a first electrical contact that physically engages a second
electrical contact of the second connector to electrically interconnect
the first and second connectors.

6. The locator as defined in claim 1, wherein the radiating element is
capable of producing an electromagnetic field.

7. The locator as defined in claim 6, further comprising a control module
for controlling operation of the radiating element.

8. The locator as defined in claim 7, wherein the control module is
capable of wirelessly transmitting at least one characteristic of the
electromagnetic field produced by the radiating element.

9. The locator as defined in claim 8, wherein the at least one
characteristic is transmitted between the control module and a component
of a system for assisting in placement of the medical device.

10. The locator as defined in claim 8, further comprising a phase locking
circuit for synchronizing a frequency of the electromagnetic field
produced by the radiating element.

11. The locator as defined in claim 8, wherein the characteristic that is
wirelessly transmitted is transmitted using one of visible, infrared, and
RF radiation.

12. A method for establishing a connection between a radiating element
included with an implantable medical device and an external sensor unit
through a sterile barrier, the method comprising:positioning the sensor
unit on a patient;placing the sterile barrier over the sensor unit;
andoperably connecting the radiating element to the sensor unit by
penetrating the sterile barrier.

13. The method for establishing a connection as defined in claim 12,
wherein the sterile barrier is a drape, and wherein operably connecting
the radiating element further comprises:piercing the drape with a
piercing element such that the sterile barrier is not compromised.

14. The method for establishing a connection as defined in claim 13,
wherein operably connecting the radiating element further
comprises:penetrating the sterile barrier with the piercing element, the
piercing element being electrically connected to the radiating element.

15. The method for establishing a connection as defined in claim 12,
wherein operably connecting the radiating element to the sensor unit
further comprises:operably connecting the radiating element located in a
sterile field to the sensor unit located outside of the sterile field.

16. The method for establishing a connection as defined in claim 15,
wherein the radiating element is removably included with the medical
device, and wherein the method further comprises:physically connecting a
tether connector operably connected to the radiating element with a
connector of the sensor unit, the sterile barrier being interposed
therebetween after the physical connection.

17. The method for establishing a connection as defined in claim 12,
further comprising:inserting the medical device including the radiating
element in the body of the patient; andmonitoring a field produced by the
radiating element.

18. A placement system for placing a catheter in a body of a patient,
comprising:a console including a display;an ultrasound probe operably
connected to the console for ultrasonically imaging a portion of the body
for depiction on the display;a radiating element included with the
catheter, the radiating element capable of producing an electromagnetic
field; andan external sensor unit operably connected to the console for
depiction on the display of information relating to detection by the
sensor unit of the electromagnetic field of the radiating element so as
to determine a position of the catheter with respect to the external
sensor during advancement of the catheter in the body.

19. The placement system as defined in claim 18, wherein the radiating
element is included with a stylet that is removably positionable in a
lumen of the catheter, and wherein the stylet includes a first connector.

20. The placement system as defined in claim 19, wherein the stylet is
positioned within a sterile field, wherein the sensor unit is positioned
outside of the sterile field, and wherein the sensor unit includes a
second connector that operably connects to the first connector of the
stylet through a sterile barrier without compromising the sterile
barrier.

21. The placement system as defined in claim 20, wherein the radiating
element of the stylet includes an electromagnetic coil that is
substantially co-terminal with a distal tip of the catheter when the
stylet is positioned in the lumen of the catheter, wherein the sterile
barrier is a drape, and wherein the first connector includes a piercing
component that pierces the drape, the piercing component including an
electrical contact.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application claims the benefit of U.S. Provisional Patent
Application No. 61/156,842, filed Mar. 2, 2009, and entitled "SYSTEM FOR
PLACEMENT OF A CATHETER INCLUDING A SIGNAL-GENERATING STYLET." This
application is also a continuation-in-part of U.S. application Ser. No.
12/426,175, filed Apr. 17, 2009, and entitled "Systems and Methods for
Breaching a Sterile Field for Intravascular Placement of a Catheter,"
which is a continuation-in-part of U.S. application Ser. No. 12/323,273,
filed Nov. 25, 2008, and entitled "Integrated System for Intravascular
Placement of a Catheter," which claims the benefit of the following U.S.
Provisional Patent Applications: Application No. 61/095,921, filed Sep.
10, 2008, and entitled "System and Method for Placing a Catheter Within a
Vasculature of a Patient;" Application No. 61/095,451, filed Sep. 9,
2008, and entitled "Catheter Assembly Including ECG and Magnetic-Based
Sensor Stylet;" Application No. 61/091,233, filed Aug. 22, 2008, and
entitled "Catheter Including Preloaded Steerable Stylet;" Application No.
61/045,944, filed Apr. 17, 2008, and entitled "Drape-Breaching Electrical
Connector;" and Application No. 60/990,242, filed Nov. 26, 2007, and
entitled "Integrated Ultrasound and Tip Location System for Intravascular
Placement of a Catheter." Each of the afore-referenced applications is
incorporated herein by reference in its entirety.

BRIEF SUMMARY

[0002]Briefly summarized, embodiments of the present invention are
directed to an integrated catheter placement system configured for
accurately placing a catheter within the vasculature of a patient. The
integrated system employs at least two modalities for improving catheter
placement accuracy: 1) ultrasound-assisted guidance for introducing the
catheter into the patient's vasculature; and 2) a tip location system
("TLS"), or magnetically-based (e.g., via permanent magnet(s) or
electromagnet(s)) tracking of the catheter tip during its advancement
through the vasculature to detect and facilitate correction of any tip
malposition during such advancement.

[0003]In one embodiment, the integrated system comprises a system console
including a control processor, a tip location sensor unit for temporary
placement on a portion of a body of the patient, and an ultrasound probe.
The tip location sensor senses a magnetic field of a stylet disposed in a
lumen of the catheter when the catheter is disposed in the vasculature.
The ultrasound probe ultrasonically images a portion of the vasculature
prior to introduction of the catheter into the vasculature. In addition,
the ultrasound probe includes user input controls for controlling use of
the ultrasound probe in an ultrasound mode and use of the tip location
sensor in a tip location mode.

[0004]In another embodiment, a third modality, i.e., ECG signal-based
catheter tip guidance, is included in the system to enable guidance of
the catheter tip to a desired position with respect to a node of the
patient's heart from which the ECG signals originate. Various means for
establishing a conductive pathway between a sterile field of the patient
and a non-sterile field to enable passage of ECG signals from the
catheter to the tip location sensor are also disclosed. Such means
include, for example, connector schemes that establish the conductive
pathway through a perforation defined in a sterile barrier, such as a
surgical drape, wherein the perforation is isolated by the connector
scheme so as to prevent contamination or compromise of the sterile field
of the patient.

[0005]In one embodiment, the tip location sensor stylet includes an
electromagnetic coil that can be operably connected to the sensor unit
and/or console through a sterile barrier without compromising the barrier
and the sterile field it at least partially defines. The stylet can also
be wirelessly connected to the sensor unit and/or console.

[0006]These and other features of embodiments of the present invention
will become more fully apparent from the following description and
appended claims, or may be learned by the practice of embodiments of the
invention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]A more particular description of the present disclosure will be
rendered by reference to specific embodiments thereof that are
illustrated in the appended drawings. It is appreciated that these
drawings depict only typical embodiments of the invention and are
therefore not to be considered limiting of its scope. Example embodiments
of the invention will be described and explained with additional
specificity and detail through the use of the accompanying drawings in
which:

[0008]FIG. 1 is a block diagram depicting various elements of an
integrated system for intravascular placement of a catheter, according to
one example embodiment of the present invention;

[0009]FIG. 2 is a simplified view of a patient and a catheter being
inserted therein with assistance of the integrated system of FIG. 1;

[0010]FIGS. 3A and 3B are views of a probe of the integrated system of
FIG. 1;

[0011]FIG. 4 is a screenshot of an ultrasound image as depicted on a
display of the integrated system of FIG. 1;

[0012]FIG. 5 is a perspective view of a stylet employed in connection with
the system of FIG. 1 in placing a catheter within a patient vasculature;

[0013]FIG. 6 is an icon as depicted on a display of the integrated system
of FIG. 1, indicating a position of a distal end of the stylet of FIG. 5
during catheter tip placement procedures;

[0014]FIGS. 7A-7E depict various example icons that can be depicted on the
display of the integrated system of FIG. 1 during catheter tip placement
procedures;

[0015]FIGS. 8A-8C are screenshots of images depicted on a display of the
integrated system of FIG. 1 during catheter tip placement procedures;

[0016]FIG. 9 is a block diagram depicting various elements of an
integrated system for intravascular placement of a catheter, according to
another example embodiment of the present invention;

[0017]FIG. 10 is a simplified view of a patient and a catheter being
inserted therein with assistance of the integrated system of FIG. 9;

[0018]FIG. 11 is a perspective view of a stylet employed in connection
with the integrated system of FIG. 9 in placing a catheter within a
patient vasculature;

[0019]FIGS. 12A-12E are various views of portions of the stylet of FIG.
11;

[0020]FIGS. 13A-13D are various views of a fin connector assembly for use
with the integrated system of FIG. 9;

[0021]FIGS. 13E-13F are various views of a tether connector for use with
the fin connector assembly shown in FIGS. 13A-13D;

[0022]FIGS. 14A-14C are views showing the connection of a stylet tether
and fin connector to a sensor of the integrated system of FIG. 9;

[0023]FIG. 15 is a cross sectional view of the connection of the stylet
tether, fin connector, and sensor shown in FIG. 14c;

[0024]FIG. 16 is simplified view of an ECG trace of a patient;

[0025]FIG. 17 is a screenshot of an image depicted on a display of the
integrated system of FIG. 9 during catheter tip placement procedures;

[0026]FIG. 18 is a cross sectional view of a fin connector including
electrical contacts configured in accordance with one embodiment;

[0027]FIGS. 19A and 19B are simplified views of an electrical contact
retention system for engagement of a tether connector with a fin
connector, in accordance with one embodiment;

[0028]FIGS. 20A-20C are various views of one embodiment of a fin connector
and a tether connector for establishing a signal pathway through a
sterile barrier in connection with use of the integrated system described
herein;

[0029]FIGS. 21A and 21B are various views of a connector for electrically
connecting ECG electrodes to a sensor of the integrated system, according
to one embodiment;

[0030]FIGS. 22A-22C are various views of one embodiment of a fin connector
and a tether connector for establishing a signal pathway through a
sterile barrier;

[0031]FIGS. 23A and 23B are cross sectional views of a connector system
for establishing a signal pathway through a sterile barrier, according to
one embodiment;

[0032]FIG. 24 is a simplified side view of a connector system for
establishing a signal pathway through a sterile barrier, according to one
embodiment;

[0033]FIGS. 25A and 25B are simplified side views of a connector system
for establishing a signal pathway through a sterile barrier, according to
one embodiment;

[0034]FIGS. 26A and 26B are cross sectional views of a connector system
for establishing a signal pathway through a sterile barrier, according to
one embodiment;

[0035]FIG. 27 is a simplified view of a connector system for establishing
a signal pathway through a sterile barrier, according to one embodiment;

[0036]FIG. 28 is a perspective view of stylet including a sterile shield
for use with the connector system shown in FIG. 28, according to one
embodiment;

[0037]FIGS. 29A and 29B are simplified views of the ECG module of FIG. 27,
including a connector system for establishing a signal pathway through a
sterile barrier, according to one embodiment;

[0038]FIG. 30 is a simplified view of a connector system for establishing
a signal pathway through a sterile barrier, according to one embodiment;

[0039]FIG. 31 is a simplified view of a connector system for establishing
a signal pathway through a sterile barrier, according to one embodiment;

[0040]FIG. 32 is a simplified view of elements of a connector system for
establishing a signal pathway through a sterile barrier, according to one
embodiment;

[0041]FIG. 33 is a view of a means for establishing a conductive pathway
between sterile and non-sterile fields, according to one embodiment.

[0042]FIG. 34 is a view of another means for establishing a conductive
pathway between sterile and non-sterile fields, according to one
embodiment.

[0043]FIGS. 35A-C depict exemplary P-wave waveforms.

[0044]FIG. 36 is a view of a sensor retro-fitted with a wireless module,
according to one embodiment.

[0045]FIG. 37 is a view of a retention feature for a connector, according
to one embodiment.

[0046]FIG. 38 is a simplified view of a patient and a catheter being
inserted therein with the assistance of a catheter placement system,
according to one embodiment;

[0047]FIG. 39 is a perspective view of an untethered stylet configured in
accordance with one embodiment;

[0048]FIG. 40 is a partial cross sectional view of a distal portion of the
stylet of FIG. 3;

[0049]FIG. 41 is a simplified block diagram of a module portion of the
untethered stylet of FIG. 3, together with associated components of the
console of FIG. 38;

[0050]FIG. 42 is a simplified diagram showing various components employed
in synchronizing a pulse signal frequency between a wireless stylet and a
console of the system of FIG. 38;

[0051]FIGS. 43A-43B are perspective views of the sensor unit of FIG. 10
and a tethered stylet, showing one possible connective scheme
therebetween in accordance with one embodiment; and

[0052]FIG. 44 is a partial cross sectional view of the connective scheme
of the sensor unit and tethered stylet, according to one embodiment.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

[0053]Reference will now be made to figures wherein like structures will
be provided with like reference designations. It is understood that the
drawings are diagrammatic and schematic representations of exemplary
embodiments of the present invention, and are neither limiting nor
necessarily drawn to scale.

[0054]FIGS. 1-44 depict various features of embodiments of the present
invention, which is generally directed to a catheter placement system
configured for accurately placing a catheter within the vasculature of a
patient. In one embodiment, the catheter placement system employs at
least two modalities for improving catheter placement accuracy: 1)
ultrasound-assisted guidance for introducing the catheter into the
patient's vasculature; and 2) a tip location/navigation system ("TLS"),
or magnetically-based tracking of the catheter tip during its advancement
through the tortuous vasculature path to detect and facilitate correction
of any tip malposition during such advancement. The ultrasound guidance
and tip location features of the present system according to one
embodiment are integrated into a single device for use by a clinician
placing the catheter. Integration of these two modalities into a single
device simplifies the catheter placement process and results in
relatively faster catheter placements. For instance, the integrated
catheter placement system enables ultrasound and TLS activities to be
viewed from a single display of the integrated system. Also, controls
located on an ultrasound probe of the integrated device, which probe is
maintained within the sterile field of the patient during catheter
placement, can be used to control functionality of the system, thus
precluding the need for a clinician to reach out of the sterile field in
order to control the system.

[0055]In another embodiment, a third modality, i.e., ECG signal-based
catheter tip guidance, is included in the integrated system to enable
guidance of the catheter tip to a desired position with respect to a node
of the patient's heart from which the ECG signals originate. Such
ECG-based positional assistance is also referred to herein as "tip
confirmation."

[0056]Combination of the three modalities above according to one
embodiment enables the catheter placement system to facilitate catheter
placement within the patient's vasculature with a relatively high level
of accuracy, i.e., placement of the distal tip of the catheter in a
predetermined and desired position. Moreover, because of the ECG-based
guidance of the catheter tip, correct tip placement may be confirmed
without the need for a confirmatory X-ray. This, in turn, reduces the
patient's exposure to potentially harmful x-rays, the cost and time
involved in transporting the patient to and from the x-ray department,
costly and inconvenient catheter repositioning procedures, etc.

[0057]As the ECG signal-based modality includes a need for passing ECG
signals from a catheter assembly disposed in a sterile field of a patient
to a data-receiving component of the system disposed in a non-sterile
field, embodiments of the present invention are further concerned with
various connector systems for establishing a conductive pathway through a
sterile barrier separating the sterile and non-sterile fields.

[0058]For clarity it is to be understood that the word "proximal" as used
herein refers to a direction relatively closer to a clinician, while the
word "distal" refers to a direction relatively further from the
clinician. For example, the end of a catheter placed within the body of a
patient is considered a distal end of the catheter, while the catheter
end remaining outside the body is a proximal end of the catheter. Also,
the words "including," "has," and "having," as used herein, including the
claims, shall have the same meaning as the word "comprising."

[0059]Reference is first made to FIGS. 1 and 2 which depict various
components of a catheter placement system ("system"), generally
designated at 10, configured in accordance with one example embodiment of
the present invention. As shown, the system 10 generally includes a
console 20, display 30, probe 40, and sensor 50, each of which is
described in further detail below.

[0060]FIG. 2 shows the general relation of these components to a patient
70 during a procedure to place a catheter 72 into the patient vasculature
through a skin insertion site 73. FIG. 2 shows that the catheter 72
generally includes a proximal portion 74 that remains exterior to the
patient and a distal potion 76 that resides within the patient
vasculature after placement is complete. The system 10 is employed to
ultimately position a distal tip 76A of the catheter 72 in a desired
position within the patient vasculature. In one embodiment, the desired
position for the catheter distal tip 76A is proximate the patient's
heart, such as in the lower one-third (1/3rd) portion of the
Superior Vena Cava ("SVC"). Of course, the system 10 can be employed to
place the catheter distal tip in other locations. The catheter proximal
portion 74 further includes a hub 74A that provides fluid communication
between the one or more lumens of the catheter 72 and one or more
extension legs 74B extending proximally from the hub.

[0061]An example implementation of the console 20 is shown in FIG. 8C,
though it is appreciated that the console can take one of a variety of
forms. A processor 22, including non-volatile memory such as EEPROM for
instance, is included in the console 20 for controlling system function
during operation of the system 10, thus acting as a control processor. A
digital controller/analog interface 24 is also included with the console
20 and is in communication with both the processor 22 and other system
components to govern interfacing between the probe 40, sensor 50, and
other system components.

[0062]The system 10 further includes ports 52 for connection with the
sensor 50 and optional components 54 including a printer, storage media,
keyboard, etc. The ports in one embodiment are USB ports, though other
port types or a combination of port types can be used for this and the
other interfaces connections described herein. A power connection 56 is
included with the console 20 to enable operable connection to an external
power supply 58. An internal battery 60 can also be employed, either with
or exclusive of an external power supply. Power management circuitry 59
is included with the digital controller/analog interface 24 of the
console to regulate power use and distribution.

[0063]The display 30 in the present embodiment is integrated into the
console 20 and is used to display information to the clinician during the
catheter placement procedure. In another embodiment, the display may be
separate from the console. As will be seen, the content depicted by the
display 30 changes according to which mode the catheter placement system
is in: US, TLS, or in other embodiments, ECG tip confirmation. In one
embodiment, a console button interface 32 (see FIGS. 1, 8C) and buttons
included on the probe 40 can be used to immediately call up a desired
mode to the display 30 by the clinician to assist in the placement
procedure. In one embodiment, information from multiple modes, such as
TLS and ECG, may be displayed simultaneously, such as in FIG. 17. Thus,
the single display 30 of the system console 20 can be employed for
ultrasound guidance in accessing a patient's vasculature, TLS guidance
during catheter advancement through the vasculature, and (as in later
embodiments) ECG-based confirmation of catheter distal tip placement with
respect to a node of the patient's heart. In one embodiment, the display
30 is an LCD device.

[0064]FIGS. 3A and 3B depict features of the probe 40 according to one
embodiment. The probe 40 is employed in connection with the first
modality mentioned above, i.e., ultrasound ("US")-based visualization of
a vessel, such as a vein, in preparation for insertion of the catheter 72
into the vasculature. Such visualization gives real time ultrasound
guidance for introducing the catheter into the vasculature of the patient
and assists in reducing complications typically associated with such
introduction, including inadvertent arterial puncture, hematoma,
pneumothorax, etc.

[0065]The handheld probe 40 includes a head 80 that houses a piezoelectric
array for producing ultrasonic pulses and for receiving echoes thereof
after reflection by the patient's body when the head is placed against
the patient's skin proximate the prospective insertion site 73 (FIG. 2).
The probe 40 further includes a plurality of control buttons 84, which
can be included on a button pad 82. In the present embodiment, the
modality of the system 10 can be controlled by the control buttons 84,
thus eliminating the need for the clinician to reach out of the sterile
field, which is established about the patient insertion site prior to
catheter placement, to change modes via use of the console button
interface 32.

[0066]As such, in one embodiment a clinician employs the first (US)
modality to determine a suitable insertion site and establish vascular
access, such as with a needle or introducer, then with the catheter. The
clinician can then seamlessly switch, via button pushes on the probe
button pad 82, to the second (TLS) modality without having to reach out
of the sterile field. The TLS mode can then be used to assist in
advancement of the catheter 72 through the vasculature toward an intended
destination.

[0067]FIG. 1 shows that the probe 40 further includes button and memory
controller 42 for governing button and probe operation. The button and
memory controller 42 can include non-volatile memory, such as EEPROM, in
one embodiment. The button and memory controller 42 is in operable
communication with a probe interface 44 of the console 20, which includes
a piezo input/output component 44A for interfacing with the probe
piezoelectric array and a button and memory input/output component 44B
for interfacing with the button and memory controller 42.

[0068]FIG. 4 shows an example screenshot 88 as depicted on the display 30
while the system 10 is in its first ultrasound modality. An image 90 of a
subcutaneous region of the patient 70 is shown, depicting a cross section
of a vein 92. The image 90 is produced by operation of the piezoelectric
array of the probe 40. also included on the display screenshot 88 is a
depth scale indicator 94, providing information regarding the depth of
the image 90 below the patient's skin, a lumen size scale 96 that
provides information as to the size of the vein 92 relative to standard
catheter lumen sizes, and other indicia 98 that provide information
regarding status of the system 10 or possible actions to be taken, e.g.,
freeze frame, image templates, data save, image print, power status,
image brightness, etc.

[0069]Note that while a vein is depicted in the image 90, other body
lumens or portions can be imaged in other embodiments. Note that the US
mode shown in FIG. 4 can be simultaneously depicted on the display 30
with other modes, such as the TLS mode, if desired. In addition to the
visual display 30, aural information, such as beeps, tones, etc., can
also be employed by the system 10 to assist the clinician during catheter
placement. Moreover, the buttons included on the probe 40 and the console
button interface 32 can be configured in a variety of ways, including the
use of user input controls in addition to buttons, such as slide
switches, toggle switches, electronic or touch-sensitive pads, etc.
Additionally, both US and TLS activities can occur simultaneously or
exclusively during use of the system 10.

[0070]As just described, the handheld ultrasound probe 40 is employed as
part of the integrated catheter placement system 10 to enable US
visualization of the peripheral vasculature of a patient in preparation
for transcutaneous introduction of the catheter. In the present example
embodiment, however, the probe is also employed to control functionality
of the TLS portion, or second modality, of the system 10 when navigating
the catheter toward its desired destination within the vasculature as
described below. Again, as the probe 40 is used within the sterile field
of the patient, this feature enables TLS functionality to be controlled
entirely from within the sterile field. Thus the probe 40 is a
dual-purpose device, enabling convenient control of both US and TLS
functionality of the system 10 from the sterile field. In one embodiment,
the probe can also be employed to control some or all ECG-related
functionality, or third modality, of the catheter placement system 10, as
described further below.

[0071]The catheter placement system 10 further includes the second
modality mentioned above, i.e., the magnetically-based catheter TLS, or
tip location system. The TLS enables the clinician to quickly locate and
confirm the position and/or orientation of the catheter 72, such as a
peripherally-inserted central catheter ("PICC"), central venous catheter
("CVC"), or other suitable catheter, during initial placement into and
advancement through the vasculature of the patient 70. Specifically, the
TLS modality detects a magnetic field generated by a magnetic
element-equipped tip location stylet, which is pre-loaded in one
embodiment into a longitudinally defined lumen of the catheter 72, thus
enabling the clinician to ascertain the general location and orientation
of the catheter tip within the patient body. In one embodiment, the
magnetic assembly can be tracked using the teachings of one or more of
the following U.S. Pat. Nos. 5,775,322; 5,879,297; 6,129,668; 6,216,028;
and 6,263,230. The contents of the afore-mentioned U.S. patents are
incorporated herein by reference in their entireties. The TLS also
displays the direction in which the catheter tip is pointing, thus
further assisting accurate catheter placement. The TLS further assists
the clinician in determining when a malposition of the catheter tip has
occurred, such as in the case where the tip has deviated from a desired
venous path into another vein.

[0072]As mentioned, the TLS utilizes a stylet to enable the distal end of
the catheter 72 to be tracked during its advancement through the
vasculature. FIG. 5 gives an example of such a stylet 100, which includes
a proximal end 100A and a distal end 100B. A handle is included at the
stylet proximal end 100A, with a core wire 104 extending distally
therefrom. A magnetic assembly is disposed distally of the core wire 104.
The magnetic assembly includes one or more magnetic elements 106 disposed
adjacent one another proximate the stylet distal end 100B and
encapsulated by tubing 108. In the present embodiment, a plurality of
magnetic elements 106 is included, each element including a solid,
cylindrically shaped ferromagnetic stacked end-to-end with the other
magnetic elements. An adhesive tip 110 can fill the distal tip of the
tubing 108, distally to the magnetic elements 106.

[0073]Note that in other embodiments, the magnetic elements may vary from
the design in not only shape, but also composition, number, size,
magnetic type, and position in the stylet distal segment. For example, in
one embodiment, the plurality of ferromagnetic magnetic elements is
replaced with an electromagnetic assembly, such as an electromagnetic
coil, which produces a magnetic field for detection by the sensor.
Another example of an assembly usable here can be found in U.S. Pat. No.
5,099,845 entitled "Medical Instrument Location Means," which is
incorporated herein by reference in its entirety. Yet other examples of
stylets including magnetic elements that can be employed with the TLS
modality can be found in U.S. application Ser. No. 11/466,602, filed Aug.
23, 2006, and entitled "Stylet Apparatuses and Methods of Manufacture,"
which is incorporated herein by reference in its entirety. These and
other variations are therefore contemplated by embodiments of the present
invention. It should appreciated herein that "stylet" as used herein can
include any one of a variety of devices configured for removable
placement within a lumen of the catheter to assist in placing a distal
end of the catheter in a desired location within the patient's
vasculature.

[0074]FIG. 2 shows disposal of the stylet 100 substantially within a lumen
in the catheter 72 such that the proximal portion thereof extends
proximally from the catheter lumen, through the hub 74A and out through a
selected one of the extension legs 74B. So disposed within a lumen of the
catheter, the distal end 100B of the stylet 100 is substantially
co-terminal with the distal catheter end 76A such that detection by the
TLS of the stylet distal end correspondingly indicates the location of
the catheter distal end.

[0075]The TLS sensor 50 is employed by the system 10 during TLS operation
to detect a magnetic field produced by the magnetic elements 106 of the
stylet 100. As seen in FIG. 2, the TLS sensor 50 is placed on the chest
of the patient during catheter insertion. The TLS sensor 50 is placed on
the chest of the patient in a predetermined location, such as through the
use of external body landmarks, to enable the magnetic field of the
stylet magnetic elements 106, disposed in the catheter 72 as described
above, to be detected during catheter transit through the patient
vasculature. Again, as the magnetic elements 106 of the stylet magnetic
assembly are co-terminal with the distal end 76A of the catheter 72 (FIG.
2), detection by the TLS sensor 50 of the magnetic field of the magnetic
elements provides information to the clinician as to the position and
orientation of the catheter distal end during its transit.

[0076]In greater detail, the TLS sensor 50 is operably connected to the
console 20 of the system 10 via one or more of the ports 52, as shown in
FIG. 1. Note that other connection schemes between the TLS sensor and the
system console can also be used without limitation. As just described,
the magnetic elements 106 are employed in the stylet 100 to enable the
position of the catheter distal end 76A (FIG. 2) to be observable
relative to the TLS sensor 50 placed on the patient's chest. Detection by
the TLS sensor 50 of the stylet magnetic elements 106 is graphically
displayed on the display 30 of the console 20 during TLS mode. In this
way, a clinician placing the catheter is able to generally determine the
location of the catheter distal end 76A within the patient vasculature
relative to the TLS sensor 50 and detect when catheter malposition, such
as advancement of the catheter along an undesired vein, is occurring.

[0077]FIGS. 6 and 7A-7E show examples of icons that can be used by the
console display 30 to depict detection of the stylet magnetic elements
106 by the TLS sensor 50. In particular, FIG. 6 shows an icon 114 that
depicts the distal portion of the stylet 100, including the magnetic
elements 106 as detected by the TLS sensor 50 when the magnetic elements
are positioned under the TLS sensor. As the stylet distal end 100B is
substantially co-terminal with the distal end 76A of the catheter 72, the
icon indicates the position and orientation of the catheter distal end.
FIGS. 7A-7E show various icons that can be depicted on the on the console
display 30 when the magnetic elements 106 of the stylet 100 are not
positioned directly under a portion of the TLS sensor 50, but are
nonetheless detected nearby. The icons can include half-icons 114A and
quarter-icons 114B that are displayed according to the position of the
stylet magnetic assembly, i.e., the magnetic elements 106 in the present
embodiment, relative to the TLS sensor 50.

[0078]FIGS. 8A-8C depict screenshots taken from the display 30 of the
system 10 while in TLS mode, showing how the magnetic assembly of the
stylet 100 is depicted. The screenshot 118 of FIG. 8A shows a
representative image 120 of the TLS sensor 50. Other information is
provided on the display screenshot 118, including a depth scale indicator
124, status/action indicia 126, and icons 128 corresponding to the button
interface 32 included on the console 20 (FIG. 8C). Though the icons 128
in the present embodiment are simply indicators to guide the user in
identifying the purpose of the corresponding buttons of the button
interface 32, in another embodiment the display can be made
touch-sensitive so that the icons themselves can function as button
interfaces and can change according to the mode the system is in.

[0079]During initial stages of catheter advancement through the patient's
vasculature after insertion therein, the distal end 76A of the catheter
72, having the stylet distal end 100B substantially co-terminal
therewith, is relatively distant from the TLS sensor 50. As such, the
display screenshot will indicate "no signal," indicating that the
magnetic field from the stylet magnetic assembly has not been detected.
In FIG. 8B, the magnetic assembly proximate the stylet distal end 100B
has advanced sufficiently close to the TLS sensor 50 to be detected
thereby, though it is not yet under the sensor. This is indicated by the
half-icon 114A shown to the left of the sensor image 120, representing
the stylet magnetic assembly being positioned to the right of the TLS
sensor 50 from the perspective of the patient.

[0080]In FIG. 8C, the magnetic assembly proximate the stylet distal end
100B has advanced under the TLS sensor 50 such that its position and
orientation relative thereto is detected by the TLS sensor. This is
indicated by the icon 114 on the sensor image 120. Note that the button
icons 128 provide indications of the actions that can be performed by
pressing the corresponding buttons of the console button interface 32. As
such, the button icons 128 can change according to which modality the
system 10 is in, thus providing flexibility of use for the button
interface 32. Note further that, as the button pad 82 of the probe 40
(FIG. 3A, 3B) includes buttons 84 that mimic several of the buttons of
the button interface 32, the button icons 128 on the display 30 provide a
guide to the clinician for controlling the system 10 with the probe
buttons 84 while remaining in the sterile field. For instance, if the
clinician has need to leave TLS mode and return to US (ultrasound) mode,
the appropriate control button 84 on the probe button pad 82 can be
depressed, and the US mode can be immediately called up, with the display
30 refreshing to accommodate the visual information needed for US
functionality, such as that shown in FIG. 4. This is accomplished without
a need for the clinician to reach out of the sterile field.

[0081]Reference is now made to FIGS. 9 and 10 in describing the integrated
catheter placement system 10 according to another example embodiment. As
before, the integrated system 10 includes the console 20, display 30,
probe 40 for US functionality, and the TLS sensor 50 for tip location
functionality as described above. Note that the system 10 depicted in
FIGS. 9 and 10 is similar in many respects to the system shown in FIGS. 1
and 2. As such, only selected differences will be discussed below. The
system 10 of FIGS. 9 and 10 includes additional functionality wherein
determination of the proximity of the catheter distal tip 76A relative to
a sin θ-atrial ("SA") or other electrical impulse-emitting node of
the heart of the patient 70 can be determined, thus providing enhanced
ability to accurately place the catheter distal tip in a desired location
proximate the node. Also referred to herein as "ECG" or "ECG-based tip
confirmation," this third modality of the system 10 enables detection of
ECG signals from the SA node in order to place the catheter distal tip in
a desired location within the patient vasculature. Note that the US, TLS,
and ECG modalities are seamlessly combined in the present system 10, but
can be employed in concert or individually to assist in catheter
placement. In one embodiment, it is understood that the ECG modality as
described herein can be included in a stand-alone system without the
inclusion of the US and TLS modalities. Thus, the environments in which
the embodiments herein are described are understood as merely example
environments and are not considered limiting of the present disclosure.

[0082]FIGS. 9 and 10 show the addition to the system 10 of a stylet 130
configured in accordance with the present embodiment. As an overview, the
catheter stylet 130 is removably predisposed within the lumen of the
catheter 72 being inserted into the patient 70 via the insertion site 73.
The stylet 130, in addition to including a magnetic assembly for the
magnetically-based TLS modality, includes a sensing component, i.e., an
ECG sensor assembly, proximate its distal end and including a portion
that is co-terminal with the distal end of the catheter tip for sensing
ECG signals produced by the SA node. In contrast to the previous
embodiment, the stylet 130 includes a tether 134 extending from its
proximal end that operably connects to the TLS sensor 50. As will be
described in further detail, the stylet tether 134 permits ECG signals
detected by the ECG sensor assembly included on a distal portion of the
stylet 130 to be conveyed to the TLS sensor 50 during confirmation of the
catheter tip location as part of the ECG signal-based tip confirmation
modality. Reference and ground ECG lead/electrode pairs 158 attach to the
body of the body of the patient 70 and are operably attached to the TLS
sensor 50 to enable the system to filter out high level electrical
activity unrelated to the electrical activity of the SA node of the
heart, thus enabling the ECG-based tip confirmation functionality.
Together with the reference and ground signals received from the ECG
lead/electrode pairs 158 placed on the patient's skin, the ECG signals
sensed by the stylet ECG sensor assembly are received by the TLS sensor
50 positioned on the patient's chest (FIG. 10) or other designated
component of the system 10. The TLS sensor 50 and/or console processor 22
can process the ECG signal data to produce an electrocardiogram waveform
on the display 30, as will be described. In the case where the TLS sensor
50 processes the ECG signal data, a processor is included therein to
perform the intended functionality. If the console 20 processes the ECG
signal data, the processor 22, controller 24, or other processor can be
utilized in the console to process the data.

[0083]Thus, as it is advanced through the patient vasculature, the
catheter 72 equipped with the stylet 130 as described above can advance
under the TLS sensor 50, which is positioned on the chest of the patient
as shown in FIG. 10. This enables the TLS sensor 50 to detect the
position of the magnetic assembly of the stylet 130, which is
substantially co-terminal with the distal tip 76A of the catheter as
located within the patient's vasculature. The detection by the TLS sensor
50 of the stylet magnetic assembly is depicted on the display 30 during
ECG mode. The display 30 further depicts during ECG mode an ECG
electrocardiogram waveform produced as a result of patient heart's
electrical activity as detected by the ECG sensor assembly of the stylet
130. In greater detail, the ECG electrical activity of the SA node,
including the P-wave of the waveform, is detected by the ECG sensor
assembly of the stylet (described below) and forwarded to the TLS sensor
50 and console 20. The ECG electrical activity is then processed for
depiction on the display 30. A clinician placing the catheter can then
observe the ECG data to determine optimum placement of the distal tip 76A
of the catheter 72, such as proximate the SA node in one embodiment. In
one embodiment, the console 20 includes the electronic components, such
as the processor 22 (FIG. 9), necessary to receive and process the
signals detected by the stylet ECG sensor assembly. In another
embodiment, the TLS sensor 50 can include the necessary electronic
components processing the ECG signals.

[0084]As already discussed, the display 30 is used to display information
to the clinician during the catheter placement procedure. The content of
the display 30 changes according to which mode the catheter placement
system is in: US, TLS, or ECG. Any of the three modes can be immediately
called up to the display 30 by the clinician, and in some cases
information from multiple modes, such as TLS and ECG, may be displayed
simultaneously. In one embodiment, as before, the mode the system is in
may be controlled by the control buttons 84 included on the handheld
probe 40, thus eliminating the need for the clinician to reach out of the
sterile field (such as touching the button interface 32 of the console
20) to change modes. Thus, in the present embodiment the probe 40 is
employed to also control some or all ECG-related functionality of the
system 10. Note that the button interface 32 or other input
configurations can also be used to control system functionality. Also, in
addition to the visual display 30, aural information, such as beeps,
tones, etc., can also be employed by the system to assist the clinician
during catheter placement.

[0085]Reference is now made to FIGS. 11-12E in describing various details
of one embodiment of the stylet 130 that is removably loaded into the
catheter 72 and employed during insertion to position the distal tip 76A
of the catheter in a desired location within the patient vasculature. As
shown, the stylet 130 as removed from the catheter defines a proximal end
130A and a distal end 130B. A connector 132 is included at the proximal
stylet end 130A, and a tether 134 extends distally from the connector and
attaches to a handle 136. A core wire 138 extends distally from the
handle 136. The stylet 130 is pre-loaded within a lumen of the catheter
72 in one embodiment such that the distal end 130B is substantially
flush, or co-terminal, with the catheter opening at the distal end 76A
thereof (FIG. 10), and such that a proximal portion of the core wire 138,
the handle 136, and the tether 134 extend proximally from a selected one
of the extension tubes 74B. Note that, though described herein as a
stylet, in other embodiments a guidewire or other catheter guiding
apparatus could include the principles of the embodiment described
herein.

[0086]The core wire 138 defines an elongate shape and is composed of a
suitable stylet material including stainless steel or a memory material
such as, in one embodiment, a nickel and titanium-containing alloy
commonly known by the acronym "nitinol." Though not shown here,
manufacture of the core wire 138 from nitinol in one embodiment enables
the portion of the core wire corresponding to a distal segment of the
stylet to have a pre-shaped bent configuration so as to urge the distal
portion of the catheter 72 into a similar bent configuration. In other
embodiments, the core wire includes no pre-shaping. Further, the nitinol
construction lends torqueability to the core wire 138 to enable a distal
segment of the stylet 130 to be manipulated while disposed within the
lumen of the catheter 72, which in turn enables the distal portion of the
catheter to be navigated through the vasculature during catheter
insertion.

[0087]The handle 136 is provided to enable insertion/removal of the stylet
from the catheter 72. In embodiments where the stylet core wire 138 is
torqueable, the handle 136 further enables the core wire to be rotated
within the lumen of the catheter 72, to assist in navigating the catheter
distal portion through the vasculature of the patient 70.

[0088]The handle 136 attaches to a distal end of the tether 134. In the
present embodiment, the tether 134 is a flexible, shielded cable housing
one or more conductive wires electrically connected both to the core wire
138, which acts as the ECG sensor assembly referred to above, and the
tether connector 132. As such, the tether 134 provides a conductive
pathway from the distal portion of the core wire 138 through to the
tether connector 132 at proximal end 130A of the stylet 130. As will be
explained, the tether connector 132 is configured for operable connection
to the TLS sensor 50 on the patient's chest for assisting in navigation
of the catheter distal tip 76A to a desired location within the patient
vasculature.

[0089]As seen in FIGS. 12B-12D, a distal portion of the core wire 138 is
gradually tapered, or reduced in diameter, distally from a junction point
142. A sleeve 140 is slid over the reduced-diameter core wire portion.
Though of relatively greater diameter here, the sleeve in another
embodiment can be sized to substantially match the diameter of the
proximal portion of the stylet core wire. The stylet 130 further includes
a magnetic assembly disposed proximate the distal end 130B thereof for
use during TLS mode. The magnetic assembly in the illustrated embodiment
includes a plurality of magnetic elements 144 interposed between an outer
surface of the reduced-diameter core wire 138 and an inner surface of the
sleeve 140 proximate the stylet distal end 130B. In the present
embodiment, the magnetic elements 144 include 20 ferromagnetic magnets of
a solid cylindrical shape stacked end-to-end in a manner similar to the
stylet 100 of FIG. 2. In other embodiments, however, the magnetic
element(s) may vary from this design in not only shape, but also
composition, number, size, magnetic type, and position in the stylet. For
example, in one embodiment the plurality of magnets of the magnetic
assembly is replaced with an electromagnetic coil that produces a
magnetic field for detection by the TLS sensor. These and other
variations are therefore contemplated by embodiments of the present
invention.

[0090]The magnetic elements 144 are employed in the stylet 130 distal
portion to enable the position of the stylet distal end 130B to be
observable relative to the TLS sensor 50 placed on the patient's chest.
As has been mentioned, the TLS sensor 50 is configured to detect the
magnetic field of the magnetic elements 144 as the stylet advances with
the catheter 72 through the patient vasculature. In this way, a clinician
placing the catheter 72 is able to generally determine the location of
the catheter distal end 76A within the patient vasculature and detect
when catheter malposition is occurring, such as advancement of the
catheter along an undesired vein, for instance.

[0091]The stylet 130 further includes the afore-mentioned ECG sensor
assembly, according to one embodiment. The ECG sensor assembly enables
the stylet 130, disposed in a lumen of the catheter 72 during insertion,
to be employed in detecting an intra-atrial ECG signal produced by an SA
or other node of the patient's heart, thereby allowing for navigation of
the distal tip 76A of the catheter 72 to a predetermined location within
the vasculature proximate the patient's heart. Thus, the ECG sensor
assembly serves as an aide in confirming proper placement of the catheter
distal tip 76A.

[0092]In the embodiment illustrated in FIGS. 11-12E, the ECG sensor
assembly includes a distal portion of the core wire 138 disposed
proximate the stylet distal end 130B. The core wire 138, being
electrically conductive, enables ECG signals to be detected by the distal
end thereof and transmitted proximally along the core wire. A conductive
material 146, such as a conductive epoxy, fills a distal portion of the
sleeve 140 adjacent the distal termination of the core wire 138 so as to
be in conductive communication with the distal end of the core wire. This
in turn increases the conductive surface of the distal end 130B of the
stylet 130 so as to improve its ability to detect ECG signals.

[0093]Before catheter placement, the stylet 130 is loaded into a lumen of
the catheter 72. Note that the stylet 130 can come preloaded in the
catheter lumen from the manufacturer, or loaded into the catheter by the
clinician prior to catheter insertion. The stylet 130 is disposed within
the catheter lumen such that the distal end 130B of the stylet 130 is
substantially co-terminal with the distal tip 76A of the catheter 72,
thus placing the distal tips of both the stylet and the catheter in
substantial alignment with one another. The co-terminality of the
catheter 72 and stylet 130 enables the magnetic assembly to function with
the TLS sensor 50 in TLS mode to track the position of the catheter
distal tip 76A as it advances within the patient vasculature, as has been
described. Note, however, that for the tip confirmation functionality of
the system 10, the distal end 130B of the stylet 130 need not be
co-terminal with the catheter distal end 76A. Rather, all that is
required is that a conductive path between the vasculature and the ECG
sensor assembly, in this case the core wire 138, be established such that
electrical impulses of the SA node or other node of the patient's heart
can be detected. This conductive path in one embodiment can include
various components including saline solution, blood, etc.

[0094]In one embodiment, once the catheter 72 has been introduced into the
patient vasculature via the insertion site 73 (FIG. 10) the TLS mode of
the system 10 can be employed as already described to advance the
catheter distal tip 76A toward its intended destination proximate the SA
node. Upon approaching the region of the heart, the system 10 can be
switched to ECG mode to enable ECG signals emitted by the SA node to be
detected. As the stylet-loaded catheter is advanced toward the patient's
heart, the electrically conductive ECG sensor assembly, including the
distal end of the core wire 138 and the conductive material 146, begins
to detect the electrical impulses produced by the SA node. As such, the
ECG sensor assembly serves as an electrode for detecting the ECG signals.
The elongate core wire 138 proximal to the core wire distal end serves as
a conductive pathway to convey the electrical impulses produced by the SA
node and received by the ECG sensor assembly to the tether 134.

[0095]The tether 134 conveys the ECG signals to the TLS sensor 50
temporarily placed on the patient's chest. The tether 134 is operably
connected to the TLS sensor 50 via the tether connector 132 or other
suitable direct or indirect connective configuration. As described, the
ECG signal can then be processed and depicted on the system display 30
(FIG. 9, 10). Monitoring of the ECG signal received by the TLS sensor 50
and displayed by the display 30 enables a clinician to observe and
analyze changes in the signal as the catheter distal tip 76A advances
toward the SA node. When the received ECG signal matches a desired
profile, the clinician can determine that the catheter distal tip 76A has
reached a desired position with respect to the SA node. As mentioned, in
one embodiment this desired position lies within the lower one-third
(1/3rd) portion of the SVC.

[0096]The ECG sensor assembly and magnetic assembly can work in concert in
assisting a clinician in placing a catheter within the vasculature.
Generally, the magnetic assembly of the stylet 130 assists the clinician
in generally navigating the vasculature from initial catheter insertion
so as to place the distal end 76A of the catheter 72 in the general
region of the patient's heart. The ECG sensor assembly can then be
employed to guide the catheter distal end 76A to the desired location
within the SVC by enabling the clinician to observe changes in the ECG
signals produced by the heart as the stylet ECG sensor assembly
approaches the SA node. Again, once a suitable ECG signal profile is
observed, the clinician can determine that the distal ends of both the
stylet 130 and the catheter 72 have arrived at the desired location with
respect to the patient's heart. Once it has been positioned as desired,
the catheter 72 may be secured in place and the stylet 130 removed from
the catheter lumen. It is noted here that the stylet may include one of a
variety of configurations in addition to what is explicitly described
herein. In one embodiment, the stylet can attach directly to the console
instead of an indirect attachment via the TLS sensor. In another
embodiment, the structure of the stylet 130 that enables its TLS and
ECG-related functionalities can be integrated into the catheter structure
itself. For instance, the magnetic assembly and/or ECG sensor assembly
can, in one embodiment, be incorporated into the wall of the catheter.

[0097]FIGS. 13A-15 describe various details relating to the passage of ECG
signal data from the stylet tether 134 to the TLS sensor 50 positioned on
the patient's chest, according the present embodiment. In particular,
this embodiment is concerned with passage of ECG signal data from a
sterile field surrounding the catheter 72 and insertion site 73, which
includes the stylet 130 and tether 134, and a non-sterile field, such as
the patient's chest on which the TLS sensor is positioned. Such passage
should not disrupt the sterile field so that the sterility thereof is
compromised. A sterile drape that is positioned over the patient 70
during the catheter insertion procedure defines the majority of the
sterile field: areas above the drape are sterile, while areas below
(excluding the insertion site and immediately surrounding region) are
non-sterile. As will be seen, the discussion below includes at least a
first communication node associated with the stylet 130, and a second
communication node associated with the TLS sensor 50 that operably
connect with one another to enable ECG signal data transfer therebetween.

[0098]One embodiment addressing the passage of ECG signal data from the
sterile field to the non-sterile field without compromising the sterility
of the former is depicted in FIGS. 13A-15, which depict a "through-drape"
implementation also referred to as a "shark fin" implementation. In
particular, FIG. 14A shows the TLS sensor 50 as described above for
placement on the chest of the patient during a catheter insertion
procedure. The TLS sensor 50 includes on a top surface thereof a
connector base 152 defining a channel 152A in which are disposed three
electrical base contacts 154. A fin connector 156, also shown in FIGS.
13A-13D, is sized to be slidingly received by the channel 152A of the
connector base 152, as shown in FIGS. 14B and 15. Two ECG lead/electrode
pairs 158 extend from the fin connector 156 for placement on the shoulder
and torso or other suitable external locations on the patient body. The
drape-piercing tether connector 132 is configured to slidingly mate with
a portion of the fin connector 156, as will be described further below,
to complete a conductive pathway from the stylet 120, through the sterile
field to the TLS sensor 50.

[0099]FIGS. 13A-13D show further aspects of the fin connector 156. In
particular, the fin connector 156 defines a lower barrel portion 160 that
is sized to be received in the channel 152A of the connector base 152
(FIGS. 14B, 15). A hole 162 surrounded by a centering cone 164 is
included on a back end of an upper barrel portion 166. The upper barrel
portion 166 is sized to receive the tether connector 132 of the stylet
130 (FIGS. 14C, 15) such that a pin contact 170 extending into a channel
172 of the tether connector 132 (FIG. 15) is guided by the centering hole
until it seats within the hole 162 of the fin connector 156, thus
interconnecting the tether connector with the fin connector. An
engagement feature, such as the engagement feature 169 shown in FIGS. 13C
and 13D, can be included on either side of the fin connector 156 to
engage with corresponding detents 173 (FIG. 13F) on the tether connector
132 to assist with maintaining a mating between the two components. If
disengagement between the two components is desired, a sufficient reverse
pull force is applied to the tether connector 132 while holding or
securing the fin connector 156 to prevent its removal from the channel
152A of the connector base 152.

[0100]FIG. 13D shows that the fin connector 156 includes a plurality of
electrical contacts 168. In the present embodiment, three contacts 168
are included: the two forward-most contact each electrically connecting
with a terminal end of one of the ECG leads 158, and the rear contact
extending into axial proximity of the hole 162 so as to electrically
connect with the pin contact 170 of the tether connector 132 when the
latter is mated with the fin connector 156 (FIG. 15). A bottom portion of
each contact 168 of the fin connector 156 is positioned to electrically
connect with a corresponding one of the base contacts 154 of the TLS
sensor connector base 152. In one embodiment, the bottom portion of each
contact 168 includes a retention feature, such as an indentation 168A. So
configured, each contact 168 can resiliently engage a respective one of
the base contacts 154 when the fin connector 156 is received by the TLS
sensor connector base 152 such that a tip of each base contact is
received in the respective indentation 168A. This configuration provides
an additional securement (FIG. 15) to assist in preventing premature
separation of the fin connector 156 from the connector base 152. Note
that many different retention features between the base contacts 154 and
the fin contacts 168 can be included in addition to what is shown and
described herein.

[0101]FIGS. 13E and 13F depict various details of the tether connector 132
according to one embodiment, including the tether connector channel 172,
the pin contact 170 disposed in the channel, and detents 173 for
removably engaging the engagement features 169 of the fin connector 156
(FIGS. 13A-13D), as described above. FIG. 13E further shows a plurality
of gripping features 171 as an example of structure that can be included
to assist the clinician in grasping the tether connector 132.

[0102]FIG. 14B shows a first connection stage for interconnecting the
above described components, wherein the fin connector 156 is removably
mated with the TLS sensor connector base 152 by the sliding engagement of
the lower barrel portion 160 of the fin connector with the connector base
channel 152A. This engagement electrically connects the connector base
contacts 154 with the corresponding fin contacts 168 (FIG. 15).

[0103]FIG. 14c shows a second connection stage, wherein the tether
connector 132 is removably mated with the fin connector 156 by the
sliding engagement of the tether connector channel 172 with the upper
barrel portion 166 of the fin connector. This engagement electrically
connects the tether connector pin contact 170 with the back contact 168
of the fin connector 156, as best seen in FIG. 15. In the present
embodiment, the horizontal sliding movement of the tether connector 132
with respect to the fin connector 156 is in the same engagement direction
as when the fin connector is slidably mated to the sensor connector base
channel 152A (FIG. 14B). In one embodiment, one or both of the stylet
130/tether connector 132 and the fin connector 156 are disposable. Also,
the tether connector in one embodiment can be mated to the fin connector
after the fin connector has been mated to the TLS sensor, while in
another embodiment the tether connector can be first mated to the fin
connector through the surgical drape before the fin connector is mated to
the TLS sensor.

[0104]In the connection scheme shown in FIG. 14c, the stylet 130 is
operably connected to the TLS sensor 50 via the tether connector 132,
thus enabling the ECG sensor assembly of the stylet to communicate ECG
signals to the TLS sensor. In addition, the ECG lead/electrode pairs 158
are operably connected to the TLS sensor 50. In one embodiment,
therefore, the tether connector 132 is referred to as a first
communication node for the stylet 130, while the fin connector 156 is
referred to as a second communication node for the TLS sensor 50. As will
be seen, various other first and second communication nodes can be
employed to enable the establishment of a conductive pathway between the
ECG sensor assembly and the TLS sensor or other system component.

[0105]Note that various other connective schemes and structures can be
employed to establish operable communication between the stylet and the
TLS sensor. For instance, the tether connector can use a slicing contact
instead of a pin contact to pierce the drape. Or, the fin connector can
be integrally formed with the TLS sensor. These and other configurations
are therefore embraced within the scope of embodiments of the present
disclosure.

[0106]As mentioned, a drape 174 is often placed over the patient 70 and
employed as a barrier to separate a sterile field of the patient, e.g.,
areas and components above the drape and proximate to the insertion site
73 (including the catheter 72, the stylet 130, and tether 134 (FIG. 10))
from non-sterile areas outside of the sterile field, e.g., areas and
components below the drape, including the patient's chest, the sensor 50
(FIG. 10) placed on the chest, and regions immediately surrounding the
patient 70, also referred to herein as a non-sterile field. As seen in
FIG. 15, the sterile drape 174 used during catheter placement to
establish the sterile field is interposed between the interconnection of
the tether connector 132 with the fin connector 156. As just described,
the tether connector 132 includes the pin contact 170 that is configured
to pierce the drape 174 when the two components are mated. This piercing
forms a small hole, or perforation 175, in the sterile drape 174 that is
occupied by the pin contact 170, thus minimizing the size of the drape
perforation by the pin contact. Moreover, the fit between the tether
connector 132 and the fin connector 156 is such that the perforation in
sterile drape made by piercing of the pin contact 170 is enclosed by the
tether connector channel 172, thus preserving the sterility of the drape
and preventing a breach in the drape that could compromise the sterile
barrier established thereby. The tether connector channel 172 is shaped
and configured so as to fold the sterile drape 174 down prior to piercing
by the pin contact 170 such that the pin contact does not pierce the
drape until it is disposed proximate the hole 162 of the fin connector
156 and such that the drape does not bunch up within the channel. It is
noted here that the tether connector 132 and fin connector 156 are
configured so as to facilitate alignment therebetween blindly through the
opaque sterile drape 174, i.e., via palpation absent visualization by the
clinician of both components.

[0107]As already mentioned, note further that the fin contacts 168 of the
fin connector 156 as shown in FIG. 15 include the indentations 168A,
which are configured to mate with the sensor base contacts 154 in such a
way as to assist in retaining the fin connector in engagement with the
sensor base channel 152A. This in turn reduces the need for additional
apparatus to secure the fin connector 156 to the TLS sensor 50. In other
embodiments, retention features that are separate from the electrical
contacts can be employed to assist in retaining the fin connector in
engagement with the sensor base channel. In one embodiment, the base
contacts 154 can be configured as pogo pins such that they are vertically
displaceable to assist in retaining the fin connector 156.

[0108]FIG. 16 shows a typical ECG waveform 176 of a patient, including a
P-wave and a QRS complex. Generally, and with respect to the present
system 10, the amplitude of the P-wave varies as a function of distance
of the ECG sensor assembly from the SA node, which produces the P-wave of
the waveform 176. A clinician can use this relationship in determining
when the catheter tip is properly positioned proximate the heart. For
instance, in one implementation the catheter tip is desirably placed
within the lower one-third (1/3rd) of the superior vena cava, as has
been discussed. The ECG data detected by the ECG sensor assembly of the
stylet 130 is used to reproduce waveforms such as the waveform 176, for
depiction on the display 30 of the system 10 during ECG mode.

[0109]Reference is now made to FIG. 17 in describing display aspects of
ECG signal data on the display 30 when the system 10 is in ECG mode, the
third modality described further above, according to one embodiment. The
screenshot 178 of the display 30 includes elements of the TLS modality,
including a representative image 120 of the TLS sensor 50, with the icon
114 corresponding to the position of the distal end of the stylet 130
during transit through the patient vasculature. The screenshot 178
further includes a window 180 in which the current ECG waveform captured
by the ECG sensor assembly of the stylet 130 and processed by the system
10 is displayed. The window 180 is continually refreshed as new waveforms
are detected.

[0110]Window 182 includes a successive depiction of the most recent
detected ECG waveforms, and includes a refresh bar 182A, which moves
laterally to refresh the waveforms as they are detected. Window 184A is
used to display a baseline ECG waveform, captured before the ECG sensor
assembly is brought into proximity with the SA node, for comparison
purposes to assist the clinician in determining when the desired catheter
tip location has been achieved. Windows 184B and 184C can be filled by
user-selected detected ECG waveforms when the user pushes a predetermined
button on the probe 40 or the console button interface 32. The waveforms
in the windows 184B and 184C remain until overwritten by new waveforms as
a result of user selection via button pushes or other input. As in
previous modes, the depth scale 124, status/action indicia 126, and
button icons 128 are included on the display 30. An integrity indicator
186 is also included on the display 30 to give an indication of whether
the ECG lead/electrode pairs 158 are operably connected to the TLS sensor
50 and the patient 70.

[0111]As seen above, therefore, the display 30 depicts in one embodiment
elements of both the TLS and ECG modalities simultaneously on a single
screen, thus offering the clinician ample data to assist in placing the
catheter distal tip in a desired position. Note further that in one
embodiment a printout of the screenshot or selected ECG or TLS data can
be saved, printed, or otherwise preserved by the system 10 to enable
documentation of proper catheter placement.

[0112]Although the embodiments described herein relate to a particular
configuration of a catheter, such as a PICC or CVC, such embodiments are
merely exemplary. Accordingly, the principles of the present invention
can be extended to catheters of many different configurations and
designs.

[0113]FIGS. 18-19B depict examples of contact engagement configurations
for the tether connector 132 and fin connector 156. Specifically, FIG. 18
depicts the fin contacts 168 of the fin connector 156 according to one
embodiment, wherein the rear contact includes a spring clip configuration
168B for receiving the pin contact 170 (FIG. 15) of the tether connector
132 via the centering cone 164 or other aperture defined in the fin
connector. FIGS. 19A and 19B depict an engagement scheme according to
another embodiment, wherein the pin contact 170 of the tether connector
132 includes a barbed feature 170A that, when inserted into the centering
cone 164 or other aperture of the fin connector 156, engages a shoulder
168C defined on the rear fin contact 168 of the fin connector so as to
help prevent premature removal of the pin contact from the fin connector.
These embodiments thus serve as non-limiting examples of a variety of
contact configurations that can be included with the fin connector 156,
the sensor connector base 152, and the tether connector 132. Note that
unless referred to as otherwise, the contacts described herein are
understood to include electrical contacts used in establishing a
conductive pathway.

[0114]The embodiments to be described below in connection with FIGS.
20A-32 each depict an example connection scheme as a means for
establishing a conductive or other communication pathway between a
patient's sterile field and a non-sterile field, i.e., areas outside of
the sterile field. Thus, the embodiments described herein serve as
examples of structure, material, and/or compositions corresponding to the
means for establishing a conductive or other communication pathway. In
particular, various embodiments described herein disclose examples for
breaching or otherwise circumventing a sterile barrier separating the
sterile field from the non-sterile field so as to provide at least a
portion of the conductive pathway for the passage of ECG signals from a
sensing component such as the ECG sensor assembly of the stylet 130 to
the sensor 50, also referred to herein as a TLS sensor or chest sensor,
or other suitable data-receiving component of the system 10. Note that
these embodiments are merely examples of a variety of means for
establishing such a conductive or other communication pathway, and are
not to be considered limiting of the scope of the present disclosure. It
is therefore appreciated that the means for establishing a conductive or
other communication pathway can be employed for transferring ECG signals
or other information, electrical signals, optical signals, etc.

[0115]As will be seen, many of the embodiments to be described include a
tether connector, also referred to herein as a first communication node,
which is operably connected to the stylet 130 and included in the sterile
field, the tether connector is configured to operably attach to a
connector included on the sensor 50 or other suitable component of the
system 10, also referred to herein as a second communications node, which
is disposed outside of the sterile field. Note, however, that the first
communication node and second communication node are contemplated as
generally referring to various connector interfaces that provide a
conductive pathway from the sterile field to the non-sterile field to
enable the passage of ECG signals as described above. It is appreciated
that the conductive pathway is a communication pathway and includes an
electrical pathway, an optical pathway, etc. Further, the communication
node connection schemes described and contemplated herein can be employed
with systems involving the use of modalities exclusive of ECG signals for
navigation or placement of a catheter or other medical device.

[0116]Note further that the embodiments to follow that describe
configurations for breaching a drape or other non-transparent sterile
barrier are configured such that location of a communication node
disposed out-of-sight under the drape/barrier is facilitated by palpation
of the clinician, thus easing location and connection of the first and
second communication nodes. Also, many of the connector configurations
described herein can be configured as one-use, disposable components so
as to minimize concerns with infection.

[0117]Reference is now made to FIGS. 20A-20C, which depict a connection
scheme as a means for establishing a conductive pathway between sterile
and non-sterile fields, according to one embodiment. In particular, FIGS.
20A-20C depict a tether connector 232 that includes an outer housing 234
and a blade holder 236 that attaches to the outer housing. A blade
contact 238 is secured by the blade holder 236 such that the blade
contact extends into a channel 240 of the tether connector. The blade
contact 238 serves to create a slice perforation in a drape that is
interposed between the tether connector and the fin connector 256 when
the tether connector 232 is slid on to engage the fin connector in the
manner described in previous embodiments. As before, the outer housing
234 of the tether connector envelops and protects the perforation so as
to prevent contamination and compromise of the sterile field.

[0118]FIG. 20C shows that a fin connector 256 includes a fin contact 268
that is configured to physically interconnect with the blade contact 238
when the tether connector is slid on to the fin connector 256, thus
establishing a conductive pathway through the sheath so as to enable ECG
signals from an ECG sensing component, i.e., the ECG sensor assembly
described above for instance, to pass to the sensor 50 via the blade
contact 238/fin contact 268 engagement. Note that the particular
configuration of the blade and fin contacts can be varied from what is
described herein. For instance, the tether connector can include two or
more blades or contacts for engagement with corresponding fin contacts to
enable multiple conductive pathways to be established, if desired. The
engagement surfaces of the tether connector and the fin connector can
also vary from what is shown and described. In one embodiment, a light
source can be included with the fin connector or other connectors as
described herein so as to provide illumination through the drape 174 and
provide visual assistance in locating the fin connector for
interconnection with the tether connector.

[0119]As seen in FIGS. 14A and 14B, in one embodiment the ECG leads 158
are permanently connected to the fin connector 156. FIG. 21A depicts
another possible embodiment, wherein the ECG leads are removably attached
to the fin connector 156 via a connector, such as a horseshoe connector
270, best seen in FIG. 21B. FIG. 21A further shows that the fin connector
156 is permanently attached to the sensor 50. These and other variations
in the connective schemes of the various components of the system 10 are
therefore contemplated as falling within the scope of the present
disclosure. In another embodiment, the electrode of each lead is
removably attachable from the lead, such as via a snap connection, for
instance.

[0120]Reference is now made to FIGS. 22A-22C, which depict a connection
scheme as a means for establishing a conductive pathway between sterile
and non-sterile fields, according to one embodiment. In particular, FIGS.
22A-22C depict a tether connector 332 that includes a channel 372 for
slidably engaging an upper barrel 166 of a fin connector 356 disposed on
the sensor 50, in a manner similar to previous embodiments. The tether
connector 332 includes a bi-positional top cap 374 to which is attached a
pin contact 370 or other piercing contact.

[0121]The top cap 374 is positioned in an un-actuated first position,
shown in phantom in FIG. 22B, when the tether connector 332 is first slid
on to the fin connector 356. The drape, removed for clarity, is
interposed between the upper barrel 166 of the fin connector 356 and the
tether connector channel 372, similar to earlier embodiments. After the
tether connector 332 is positioned on the fin connector 356, the top cap
374 can then be depressed by the clinician into an actuated second
position shown in FIG. 22B, wherein the pin contact 370 is pressed
downward through the drape and into operable engagement with a
corresponding contact disposed in the fin connector 356. The tether
connector 332 is thus positioned as shown in FIG. 22c. In addition to
establishing a conductive path through the drape 174, this engagement of
the pin contact 370 locks the tether connector 332 on to the fin
connector 356 so as to prevent premature separation of the components.

[0122]Reference is now made to FIGS. 23A and 23B, which depict a
connection scheme as a means for establishing a conductive pathway
between sterile and non-sterile fields, according to one embodiment. In
particular, FIG. 23A depicts a tether connector 432 including a pin
contact 440 or other suitable contact attached to an actuation assembly
442. The actuation assembly 442 includes lever arms for selectively
lowering the pin contact 440 through an opening defined by a male end 448
of a housing 446 in which the actuation assembly is disposed. The male
end 448 of the housing is configured to be received by a sensor connector
receptacle 450 disposed on the sensor 50 or other suitable component of
the system, such as a remote module operably connected to the sensor, for
instance.

[0123]To interconnect the tether connector 432 to the sensor connector
receptacle 450, the male end 448 of the tether connector 432 is brought,
above the drape 174, into proximity with the receptacle 450. The
actuation assembly 442 is then actuated by raising the lever arms 444, as
shown in FIG. 23B. The pin contact 440 is forced downward through the
drape 174, thus defining a perforation therein. The male end 448 can then
be fully received into the sensor receptacle 450, wherein the pin contact
440 operably connects with a suitable contact of the sensor connector
receptacle. The connector scheme shown in FIGS. 23A and 23B is useful for
imposing a minimal downward force on the body of the patient during
connector interconnection. Further, the actuation assembly 442 provides a
predetermined force in connecting the first communication node (the
tether connector 432) with the second communication node (the sensor
connector receptacle 450), and thus does not rely on a clinician's
estimation of force to establish the node connection. In another
embodiment, the housing 446 and the sensor receptacle 450 can be aligned
and mated before the actuation assembly 442 is actuated to pierce the
contact 440 through the drape.

[0124]Reference is now made to FIG. 24, which depicts a connection scheme
as a means for establishing a conductive pathway between sterile and
non-sterile fields, according to one embodiment. As in the embodiment
shown in FIGS. 23A and 23B, the present interconnection scheme minimizes
downward pressure on the body of the patient during interconnection of
the nodes. As shown, a tether connector 532 includes a pin contact 540 or
other suitable contact included with a threaded cap 542, which defines
threads on an inside surface thereof. The threaded cap 542 is configured
to threadingly receive a threaded base 544 disposed on the sensor 50 or
other suitable component of the system, such as a remote module operably
connected to the sensor, for instance. As before, the drape 174 is
interposed therebetween.

[0125]To interconnect the tether connector 532 to the sensor 50, the
threaded cap 542 of the tether connector is brought, above the drape 174,
into proximity with the threaded base 544 and threaded on to the base.
This causes the pin contact 540 to penetrate the drape 174, thus defining
a perforation therein. Further threading of the cap 542 on to the base
544 causes the pin contact 540 to engage a contact receptacle 546
included in the base 544, thus operably interconnecting the two nodes. In
one embodiment, the tether 134 is rotatably attached to the threaded cap
542 so as to prevent twisting of the tether during threading. The
connector scheme shown in FIG. 24 is useful for imposing a minimal
downward force on the body of the patient during connector
interconnection as the force to join the two connectors is directed
laterally with respect to the patient via the threading operation. Note
further that a variety of thread configurations and locations, as well as
different cap and base configurations, are contemplated by the present
disclosure.

[0126]Reference is now made to FIGS. 25A and 25B, which depict a
connection scheme as a means for establishing a conductive pathway
between sterile and non-sterile fields, according to one embodiment. As
in the previous embodiment, the present interconnection scheme minimizes
downward pressure on the body of the patient during interconnection of
the nodes. As depicted in FIGS. 25A and 25B, a tether connector 632
includes one or more piercing contacts, such as pin contacts 640A and
640B that are respectively included on slide arms 642A and 642B. One or
more contact receptacles, such as contact receptacles 644A and 644B, are
included on a portion of the sensor 50, such as a sensor fin 646, or
other suitable system component. As before, the drape 174 is interposed
between the tether connector 632 and the sensor fin 646 to serve as a
sterile barrier.

[0127]To interconnect the tether connector 632 to the sensor fin 646, the
tether connector is brought, above the drape 174, into proximity with the
sensor fin such that the slide arms 642A and 642B straddle the sensor fin
and such that the pin contacts 640A and 640B are aligned with
corresponding contact receptacles 644A and 644B, as shown in FIG. 25A.
The slide arms 642A and 642B are then slid toward one another such that
the pin contacts 640A and 640B penetrate the drape 174, each defining a
perforation therein. The slide arms 642A and 642B are slid inward until
the pin contacts 640A and 640B seat within and operably connect with the
corresponding contact receptacles 644A and 644B, as seen in FIG. 25B,
thus interconnecting the two nodes. The connector scheme shown in FIGS.
25A and 25B is useful for imposing a minimal downward force on the body
of the patient during connector interconnection as the force to join the
two connectors is directed laterally with respect to the patient. Note
that the particular configuration of the tether connector, the sensor
fin, and the contacts can vary from what is explicitly described herein.
For instance, in one embodiment the slide arms can be configured as
bi-positional rocker arms that are connected in a see-saw configuration
with respect to one another. Also, one, two, or more contacts can be
included on the slide arms.

[0128]Reference is now made to FIGS. 26A and 26B, which depict a
connection scheme as a means for establishing a conductive pathway
between sterile and non-sterile fields, according to one embodiment. As
shown, an integrated connector 730 is incorporated into the drape 174 so
as to enable operable interconnection therethrough. In the illustrated
embodiment, the integrated connector 730 includes a conductive base
portion 734 from which extend mechanical connectors, such as snap balls
736A and 736B.

[0129]As shown in FIG. 26B, the integrated connector 730 is positioned in
the drape 174 as to be connectable with both a suitable receptacle 738 of
a tether connector 732 and a suitable receptacle 740 of the sensor 50 or
other suitable component of the system 10. In particular, the tether
connector 732 can be snap-attached to the integrated connector 730, after
which the integrated connector can be attached to the sensor 50, thus
providing a suitable pathway for signals from the ECG sensor assembly in
the sterile field to be transmitted through the sterile barrier of the
drape 174 to the sensor in the non-sterile field. It is appreciated that,
in other embodiments, the integrated connector can include other
configurations, such as different mechanical connectors, e.g., friction
connectors, male/female connectors, etc., and as such the receptacles on
the tether connector and sensor can likewise be modified to accommodate
the different mechanical connectors. Also, the connective scheme
described above can be reversed such that the receptacles are included on
the integrated connector and the snap balls on the respective tether
connector and sensor. Further, though presently depicted as a unitary
component, the integrated connector in other embodiments can include two
or more pieces that are attached to each other through a previously
defined hole in the drape during manufacture thereof. These and other
variations are therefore contemplated.

[0130]Reference is now made to FIG. 27, which depicts a connection scheme
as a means for establishing a conductive pathway between sterile and
non-sterile fields, according to one embodiment. In detail, FIG. 27
depicts an intermediate module, i.e., ECG module 750, disposed outside of
the sterile field of the patient, which is operably connected to the
sensor 50 of the system 10 via a sensor cable 752. The ECG module 750 is
also operably connected to the ECG leads 158. In one embodiment, the ECG
module 750 includes the circuitry and other components necessary for
receipt and analysis of the ECG signal detected by the ECG sensor
assembly of the stylet 130. As such, a conductive pathway is established
between the stylet 130 and the ECG module 750 by traversing the sterile
field of the patient. In the present embodiment, this is accomplished by
a tether connector 762 of the tether 134.

[0131]As depicted in FIG. 27, the tether connector 762 operably attaches
to a receptacle 764 of the ECG module 750. As shown, the tether connector
762 can include a sufficiently long handle that enables the clinician to
attach the sterile tether connector to the receptacle 764 of the
non-sterile ECG module 750 without touching the ECG module itself, thus
preventing any compromise of the sterile field. In one embodiment, the
handle of the tether connector 762 can include an extendable J-hook
contact, for instance, that can operably connect to a suitable contact of
the ECG module.

[0132]FIG. 28 shows another example of a tether connector that can be
employed with the ECG module 750 of FIG. 27 or other suitable component
of the system 10 as part of a connection scheme as a means for
establishing a conductive pathway between sterile and non-sterile fields,
according to one embodiment. In particular, FIG. 28 depicts a tether
connector 832, which includes a handle and a barbed contact 836 or other
suitable contact at a proximal end thereof. A sterile shield 838 is
interposed between the handle 834 and the contact 836. The sterile shield
838 assists in protecting the hand of the clinician while inserting the
contact 836 into the receptacle 764 of the ECG module 750 in a manner
similar to what is shown in FIG. 27. Thus, the sterile shield 838 serves
as an additional barrier to prevent inadvertent contact by the clinician
with a component outside of the sterile field, such as the ECG module
750. Note that the size, shape, and particular configuration of the
sterile shield and/or tether connector can vary from what is explicitly
described in the present embodiment.

[0133]FIGS. 29A and 29B show yet another example of a connection scheme
that can be employed with the ECG module 750 of FIG. 27 or other suitable
component of the system 10 as a means for establishing a conductive
pathway between sterile and non-sterile fields, according to one
embodiment. In particular, FIG. 29A shows that the ECG module 750 can be
enveloped by a sterile bag 850. A connector, such as the integrated
connector 730 described above in connection with FIGS. 26A and 26B, can
be incorporated into the bag. As shown in FIG. 29B, an inner snap ball or
other mechanical connector of the integrated connector 730 can be
received by the suitably corresponding receptacle 764 of the ECG module
750. The tether connector of the system 10 can then be operably connected
with the outer snap ball or other connector of the integrated connector
730, thus establishing a conductive pathway between the sterile field and
the non-sterile field without compromising sterility. Note that the
sterile bag 850 can include any one or more of a variety of suitable
materials, including plastic. Note also that the integrated connector can
include other connector configurations in addition to what is explicitly
described herein. In one embodiment, the sterile bag includes no
integrated connector, but rather is pierced by a pin contact of the
tether connector, such as the barbed contact 836 included on the tether
connector 832 of FIG. 28.

[0134]Reference is now made to FIG. 30, which depicts a connection scheme
as a means for establishing a conductive pathway between sterile and
non-sterile fields, according to one embodiment. Specifically, the stylet
130 includes a tether connector 862 as a first communication node, as in
previous embodiments. A remote sensor connector 864 is also included as a
second communications node, and is operably connected to the sensor 50 of
the system 10 via a remote sensor connector cable 866. The tether
connector 862 and remote sensor connector 864 operably connect to one
another along a connection interface 868. The drape 174 that serves as a
sterile barrier is interposed between the tether connector 862 and remote
sensor connector 864 at the connection interface 868, and a suitable
drape piercing configuration is included with the tether connector and
the remote sensor connector to establish a conductive pathway through the
drape. The present embodiment thus discloses one embodiment wherein the
second communication node is located remotely with respect to the sensor
50.

[0135]Reference is now made to FIG. 31, which depicts a connection scheme
as a means for establishing a conductive pathway between sterile and
non-sterile fields, according to one embodiment. Specifically, the
present embodiment includes the tether connector 862 and the remote
sensor connector 864 that operably connect to one another along the
connection interface 868, as described in connection with FIG. 30, above.
The remote sensor connector 864 in the present embodiment is placed
proximate the catheter insertion site 73 in a region over which a
fenestration 880 defined in the drape 174 (portions of the drape omitted
for clarity) is positioned to enable clinician access to the insertion
site during catheter placement. The remote sensor connector 864 is
adhered to the patient's skin proximate the catheter insertion site 73
with the use of an adhesive, tape, etc., before the region surrounding
the insertion site is sterilized in preparation for catheter insertion.
Thus, when the insertion site is sterilized, the remote sensor connector
864 is also sterilized. Later, when connection of the tether connector
862 to the remote sensor connector 864 is made, the clinician can handle
the latter component without compromising the sterile field of the
patient. It is appreciated that the particular configurations of the
tether connector and the remote sensor connector can vary while still
residing within the scope of the present embodiment.

[0136]Reference is now made to FIG. 32, which depicts a connection scheme
as a means for establishing a conductive pathway between sterile and
non-sterile fields, according to one embodiment. Specifically, FIG. 32
shows the probe 40 employed by the system 10 for US functionality, as
described above in connection with FIGS. 3A and 3B. A sterile sheath 900
is placed over the probe 40 so as to bring the probe into the sterile
field of the patient. A connection interface, such as a receptacle 910,
is included on the probe 900 and is configured so as to be operable
connectable with a tether connector 920. In one embodiment, for example,
the tether connector 920 includes a pin contact that penetrates the
sterile sheath 900 to mate with the receptacle 910 in such a way as to
prevent contamination of the sterile field. In this way, the tether
connector 920, as a first communication node, operably connects with the
probe 40, as a second communications node. In turn, the probe 40 is
operably connected to the system console 20, as seen in FIG. 31 for
example, so as to enable ECG signals received by the ECG sensor assembly
of the stylet 130 via the tether connector 920 to be forwarded to the
console, the sensor 50, or other system component for processing, as
described above. In another embodiment, the receptacle 910 or other
suitable connection interface can be included on the cable connecting the
probe 40 to the system console 20. The particular contact configuration
of the receptacle 910 and tether connector 920 can be varied according to
the understanding of one skilled in the art. For instance, an integrated
connector such as that shown in FIGS. 26A and 26B can be incorporated
into the sterile sheath in one embodiment. Note further that, though
including plastic in the present embodiment, the sterile sheath as
described herein can include other suitable materials for providing
sterility.

[0137]Reference is now made to FIG. 33 in describing means for
establishing a conductive pathway between sterile and non-sterile fields,
according to one embodiment. As shown, the tether 134 includes a wireless
module 950, included within the sterile field, which serves as a first
communication node for wirelessly transmitting (via RF or other suitable
frequency or frequency range) ECG data received from the ECG sensor
assembly of the stylet 130 to a data-receiving component as a second
communication node, such as the sensor 50 or other suitable component of
the system 10. A wireless module ground electrode 952 is operably
connected with the wireless module 950 for placement in the sterile field
proximate the catheter insertion site 73. A system ground electrode 158A
extends from the sensor 50 for placement outside of the sterile field but
proximate both the catheter insertion site 73 and the location of the
wireless module ground electrode 952. One possible placement location for
the system ground electrode 158A is beneath the patient arm, as depicted
in FIG. 33. The system reference electrode 158B is placed on the lower
torso of the patient 70 or other suitable location, as in previous
embodiments. Note that the wireless module and system console as
discussed herein can be configured in one or more of a variety of ways
and include components for wireless signal transmission and reception not
specifically detailed herein, such as patch or other antennas, signal
transducers, etc.

[0138]With the system configured as shown in FIG. 33, the system ground
electrode 158A can be electrically driven such that it produces a voltage
that is sensed by the passive wireless module ground electrode 952, given
its proximate location with respect to the system ground electrode. This
enables both ground electrodes to be at substantially equal electric
potentials, thus enabling the wireless module 950 to utilize the wireless
module ground electrode 952 and the ECG signals from the ECG sensor
assembly of the stylet 130, e.g., the core wire 138 (FIGS. 12C-12E) in
one embodiment, to detect and wirelessly transmit the ECG data to the
sensor 50 for comparison with the data sensed by the system reference
electrode 158B in order to obtain the desired P-wave waveform (e.g., FIG.
16). The data comparison in one embodiment is a differential comparison
between the ECG data as obtained by the ECG sensor assembly of the stylet
130, the wireless module ground electrode 952, and the system reference
electrode 158B. In one embodiment, the system ground electrode 158A, like
the wireless module ground electrode 952, can be passive and not
electrically driven. Note also that the analog ECG data can be digitized
or otherwise processed by the wireless module 950 before transmission to
the sensor 50 or other system component, such as the console 20.

[0139]FIG. 34 describes yet another wireless configuration as a means for
establishing a conductive pathway between sterile and non-sterile fields,
according to one embodiment. As shown, a positive electrode 954A at a
location A and a negative electrode 954B at a location B are included
with the sensor 50 and positioned on the torso of the patient 70, while a
positive wireless module electrode 956 is included with the wireless node
950, as indicated at location C, positioned on or in the patient
proximate the catheter insertion site 73. The ECG sensor assembly of the
stylet 130, e.g., the core wire 138 in one embodiment, serves as a
negative electrode for the wireless portion of the depicted
configuration, indicated at D in FIG. 34 at its final position. Note that
in one embodiment the locations A and B of the electrodes 954A and 954B,
respectively, can be altered on the patient body to tune the system 10
for best ECG signal reception.

[0140]In the present embodiment, the electrodes 954A and 954B serve as a
first independent source for sampling bipolar ECG signals. The ECG data
from these electrodes are digitized and forwarded to the console 20 or
other suitable system component via the cable interconnecting the sensor
50 and the console (path 1) outside of the sterile field. The wireless
module electrode 956 and the ECG sensor assembly serve as a second
independent source for sampling bipolar ECG signals. The ECG data from
these electrodes are digitized and forwarded wirelessly to the console 20
via the wireless module 950 (path 2) within the sterile field. Thus, in
the present embodiment the wireless module 950 serves as a first
communication node, and a wireless receiver of the console 20 as a second
communication node for the transfer of ECG signals between the two nodes.
Note that the polarities of the afore-mentioned electrodes can be
reversed in other embodiments.

[0141]The ECG signals received along both paths 1 and 2 are baseline
corrected by appropriate circuitry of the console 20 to adjust for DC
offset and drift. After such correction, a non-changing reference, or
baseline, P-wave waveform 176A from path 1 can be produced, as seen in
FIG. 35A, for example. Similarly, a P-wave waveform 176B as seen in FIG.
35B is produced from path 2, which waveform changes as the stylet 130
within the catheter 72 is advanced toward the heart of the patient.
During such advancement, the waveform 176B from path 2 is subtracted from
the P-wave waveform 176A from path 1, employing a digital differential
amplifier, for instance. This subtraction removes all common components
of the waveforms represented by each of the signals, and enables the
console 20 to depict via its display 30 only the differences in the two
signals, as seen for example by the waveform 176C shown in FIG. 35C. The
change in P-wave of the waveform from path 2 can then be easily observed
during catheter advancement. Thus the present embodiment enables an
easily observable digital display of ECG data to be represented while
preventing a physical breaching of a sterile barrier, such as a surgical
drape, for the passage of such data.

[0142]Note that in other embodiments the wireless module electrode 956 can
include other configurations, including a conductive element imbedded
into an introducer sheath, in contact with the bloodstream of the
patient, which is commonly disposed through the insertion site 73 during
catheter placement. The introducer can include a connector on a proximal
portion thereof to enable a connection with the wireless node 950 to be
made, in one embodiment.

[0143]Note further that one or more of a variety of wireless protocols can
be employed in transmitting wireless signals in accordance with the
embodiments described herein, including one or more of the IEEE 802.11
family of specifications, etc. Also note that in one embodiment the
wireless module can be included in a sterile sheath, as described in
previous embodiments, to bring the module within the sterile field,
together with connectors for operably connecting the wireless module
electrode through the sheath or included in the sheath itself. Of course,
other methods for maintaining the wireless module within the sterile
field can also be employed. In one embodiment, the wireless module can
include buttons that further enable control of the system 10 from within
the sterile field.

[0144]FIG. 36 shows that in one embodiment the sensor 50 can be
retro-fitted with a wireless module 960 to enable signals received by the
sensor to be wirelessly transmitted to the console 20 or other suitable
component of the system 10. For instance, ECG data received by the ground
and reference electrodes 158A, 158B (FIG. 34) can be received by the
sensor 50 then wirelessly transmitted to the system console via the
wireless module 960. The wireless module 960 can include an antenna or
other transmitting component and can operably connect to the sensor 50
via a sensor cable 962 or other suitable interface. Note that the
wireless module 960 can be employed in connection with other embodiments
described herein, including those depicted in FIGS. 10 and 33, for
instance.

[0145]FIG. 37 shows a retention feature for preventing inadvertent
separation of the fin connector 156 from the sensor connector base 152 or
other receptacle with which the fin connector operably connects,
according to one embodiment. As shown, the fin connector 156 includes a
retention arm 970 that is resiliently attached to the fin connector body.
The retention arm 970 includes a tab 972 that slides over and engages a
lip 974 included with the connector base 152 of the sensor 50 when the
fin connector 156 is slidably received in the sensor channel 152A (FIG.
14A). The engagement of the tab 972 with the lip 974 prevents inadvertent
removal of the fin connector 156 during use. When removal of the fin
connector 156 from the sensor connector base 152 is desired, the
retention arm 970 is lifted so as to disengage the tab 972 from the lip
974, after which the fin connector can be slid our of engagement with the
sensor channel 152A. This configuration can be employed either with or
independent of other retention features, such as the indentations 168A
(FIG. 13D). Note that in other embodiments a variety of modifications and
configurations can be employed in assisting to maintain engagement
between the fin connector and the connector. For instance, the retention
arm in one embodiment can be operably attached to one or more of the fin
contacts 168 (FIG. 13D) such that displacement, e.g., lifting laterally
moving, pinching, etc., of the retention arm or other suitable fin
connector component disengages the fin contact(s) from the base contacts
(FIG. 15), thus reducing the overall retention force provided by the
engagement of the fin contacts with the base contacts. Note further that
these principles can be applied to the other connector schemes disclosed
or contemplated in addition to the fin connector described here.

[0146]In addition to the above embodiments depicting various connection
schemes as means for establishing a conductive pathway between sterile
and non-sterile fields, other configurations can be employed, as
appreciated by one skilled in the art, for performing the same
functionality. Such other configurations can include, for example,
wireless transmission of ECG signals from the stylet to the sensor or the
system component, the inclusion of electrically conductive thread in the
drape, the inclusion of an electrically conductive window (e.g., composed
of an electrically conductive plastic or foil) in the sterile drape, etc.
In yet another embodiment, a proximal end of the stylet/guidewire itself
can be used to pierce the drape for receipt into a connector on the
sensor. In this case, no tether is included on the proximal end of the
stylet, and the stylet itself serves as the conductive pathway for
transmitting ECG signals from the stylet sensor assembly to the sensor on
the patient's chest. Such a configuration can allow for over-the-wire
placement of the catheter using a stylet/guidewire as described here. As
such, the above embodiments should not be construed as being limiting of
the present invention in any way.

[0147]FIGS. 38-44 describe features of embodiments relating to a radiating
element for use in assisting in the placement of an implantable medical
device, such as a catheter, within the body of a patient. The radiating
element is capable of producing a detectable electromagnetic field and in
one embodiment is included in a stylet. In particular, the stylet
includes functionality to generate an electrical pulse signal to a coil
assembly disposed at a distal end thereof. The resulting electromagnetic
field produced by the coil assembly is detectable by the sensor unit of
the catheter placement system generally described above, which is placed
in proximate relation to the patient during catheter advancement. The
stylet including the coil assembly is positioned within the catheter such
that the coil assembly is substantially co-terminal with the distal end
of the catheter, thus enabling a clinician to determine an approximate
location and/or orientation of the catheter distal end during advancement
thereof through the patient vasculature and to determine when a possible
catheter malposition has occurred. As such, the stylet described here in
connection with the present embodiment replaces the stylet including a
passive magnetic assembly described in previous embodiments further above
in connection with the catheter placement system.

[0148]In accordance with one embodiment, the stylet including the
radiating element is physically untethered to a console or other
component of the catheter placement system. Thus, the stylet itself
includes all necessary componentry for producing the electrical pulse
signal for use by the system. The stylet in one embodiment further
includes functionality to synchronize its pulsing activities with a
console of the catheter placement system such that the system can
accurately track advancement of the stylet and its corresponding catheter
through the patient vasculature. In another embodiment, the stylet
including the radiating element is tethered to the sensor unit of the
catheter placement system in such a way as to enable the passage of
driving signals from the sensor unit or system console to the radiating
element through a sterile barrier interposed between the catheter/stylet
and sensor unit or console without compromising the barrier itself or the
sterile field it helps establish.

[0149]Reference is made to FIGS. 1 and 38 which depict the various
components of the catheter placement system ("system") 10, configured in
accordance with one example embodiment, and as have already been
described further above. FIG. 38 shows the general relation of these
components to the patient 70 during a procedure to place the catheter 72
into the patient vasculature through the skin insertion site 73. As
before, the system 10 is employed in connection with positioning the
distal tip 76A of the catheter 72 in a desired position within the
patient vasculature. In one embodiment, the desired position for the
catheter distal tip 76A is proximate the patient's heart, such as in the
lower one-third portion of the SVC.

[0150]As mentioned above, the catheter placement system 10 includes a tip
location system ("TLS") modality that enables the clinician to quickly
locate and confirm the position and/or orientation of the catheter 72
during initial placement into and advancement through the vasculature of
the patient 70. Specifically, the TLS modality is configured to detect an
electromagnetic field generated by the radiating element, such as a coil
assembly included at a distal end of a stylet, which is pre-loaded in one
embodiment into a longitudinally defined lumen of the catheter 72, thus
enabling the clinician to ascertain the general location and orientation
of the catheter tip within the patient body. The TLS also displays the
direction in which the catheter tip is pointing, further assisting
accurate catheter placement. In addition, the TLS assists the clinician
in determining when a malposition of the catheter tip has occurred, such
as in the case where the tip has deviated from a desired venous path into
another vein.

[0151]As mentioned, the TLS utilizes a stylet in one embodiment to enable
the distal end of the catheter 72 to be tracked during its advancement
through the vasculature. FIGS. 38 and 39 give an example of a detached
configuration of such a stylet 100, configured in accordance with one
embodiment. In particular, the stylet 100 in FIGS. 38 and 39 is
physically detached, or untethered, from other components of the catheter
placement system 10. The stylet 100 includes a proximal end 100A and a
distal end 100B. A stylet control module 102, also referred to herein as
a "fob," is included at the stylet proximal end 100A, with an elongate
portion 1104 extending distally therefrom.

[0152]FIG. 40 gives further details regarding a distal portion of the
stylet elongate portion 104 proximate the stylet distal end 100B. A coil
assembly 1106 is included proximate the stylet distal end 100B and is
operably connected to leads 1106A. The leads 1106A are in turn operably
connected to corresponding circuitry located in the stylet control module
102 configured to produce an electric pulse signal so as to enable the
coil assembly 1106 to be electrically pulsed during operation and produce
an electromagnetic field having a predetermined frequency or pattern that
is detectable by one or more sensors included in the chest sensor 50
during transit of the catheter through the vasculature when the coil
assembly is within the detectable range of the sensor. Note that the coil
assembly described herein is but one example of a radiating element, or a
component capable of producing an electromagnetic field for detection by
the sensor. Indeed, other devices and assembly designs can be utilized
here to produce the same or similar functionality. For instance,
non-limiting examples of other stylet configurations can be found in U.S.
patent application Ser. No. 12/545,762, filed Aug. 21, 2009, and entitled
"Catheter Assembly Including ECG Sensor and Magnetic Assemblies," which
is incorporated herein by reference in its entirety. In one embodiment,
more than one radiating element can be included, with each radiating
element oriented in a different direction or spaced apart with respect to
the other(s). In another embodiment, radiating elements of different
types (e.g., ultrasonic and electromagnetic) can be included together.

[0153]The coil assembly 1106 and leads 1106A are disposed within tubing
1108 that extends at least a portion of the length of the stylet elongate
portion 1104. The coil assembly and leads can be protected in other ways
as well. A core wire 1110 can be included within the tubing 1108 in one
embodiment to offer stiffness and/or directional torqueability to the
stylet elongate portion 1104. The core wire 1110 in one embodiment
includes nitinol and can extend to the distal end 100B of the stylet 100
or terminate proximal thereto.

[0154]In accordance with the present embodiment, the stylet 100 is
untethered, or physically unconnected, with respect to the console 20 of
the system 10. As such, the electric pulsing of the coil assembly 1106 to
produce the predetermined electromagnetic field is driven by suitable
componentry included in the fob, or stylet control module 102, as opposed
to pulse driving by the console or other system component to which the
stylet would be physically connected. FIG. 41 shows such componentry
according to one example embodiment. The control module 102 includes a
housing 102A in which a printed circuit board ("PCB") 1132 or other
suitable platform is housed. Pulse circuitry 1134 is disposed on the PCB
1132 and includes a timer circuit 1136 configured to provide electrical
pulses to the coil assembly 1106 via the leads 1106A (FIG. 40). It is
noted that in one embodiment the electromagnetic field can be pulsed so
as to produce a predetermined pattern, if desired.

[0155]A connector 1130A is included on the control module housing 102A and
configured to removably and operably connect with a corresponding
connector 1130B included on a proximal end of the stylet elongate portion
1104. In this way, operable connection between the timer circuit 1136 and
the coil assembly 1106 via the leads 1106A is achieved in the present
embodiment. Note that other connective schemes between the pulse
circuitry and the coil assembly can be used. In another embodiment, the
stylet elongate portion is permanently connected to the stylet control
module.

[0156]A power supply 1140 is included with the stylet control module 102
to provide power necessary for control module functions, including
operation of the pulse circuitry 1134 and driving of the electric pulsing
performed by the timer circuit 1136. In one embodiment, the stylet 100 is
a disposable, one-time use component and as such the power supply 1140 is
also disposable, such as a button-cell battery. In other embodiments, the
power supply can be a rechargeable battery, a long-life power supply, or
can be configured to be replaceable as may be appreciated by one skilled
in the art. In one embodiment, the control module 102 includes an on/off
switch for controlling operation of the control module components.

[0157]As mentioned, the timer circuit 1136 drives the coil assembly 1106
by sending electrical pulses at a predetermined frequency to the coil
assembly via the leads 1106A to which the timer circuit is operably
connected. Receipt of the pulses causes the coil assembly 1106 to emit an
electromagnetic field having the predetermined frequency that is
detectable by the sensor unit 50 of the system 10, thus assisting
guidance of the catheter 72 (FIG. 38) as has been described.

[0158]In one embodiment, the electric pulse signal of the timer circuit
1136 is synchronized with the console 20, or other system component (such
as the sensor 50), to enable the system 10 to identify the frequency of
the field produced by the coil assembly 1106 as a result of the pulsing.
This enables the console 20 to identify the proper field relating to the
stylet coil assembly 1106 and the sensor unit 50 to accurately track
progress of the stylet 100 during intravascular advancement of the
catheter 72. The particular frequency/frequencies employed for the pulse
signal in one embodiment comply with applicable laws and regulations,
including regulations promulgated by the Federal Communications
Commission ("FCC"). In one implementation a frequency of 1 MHz may be
used, for example.

[0159]In the present embodiment, synchronization of the pulse signal
frequency produced by the timer circuit 1136 with the console 20 is
achieved by a transmitter 1138 included with the stylet control module
102, as seen in FIGS. 39 and 41. The transmitter 1138 is operably
connected to and receives data from the timer circuit 1136 relating to
the frequency of its pulse signal being sent to the coil assembly 1106.
The transmitter 1138 transmits the data to a receiver 1142 included on
the console 20. Receiving the data by the receiver 1142, the console 20
can then identify the electromagnetic field produced by the coil assembly
1106 when detected by the sensor unit 50 and thus track intravascular
advancement of the catheter 72.

[0160]In one implementation, the data transmitted by the transmitter 1138
are a message detailing the pulsing frequency of the pulse signal
produced by the timer circuit 1136. In another implementation, the data
are merely a replication of the pulse signal itself that, when received
by the console 20, enable the console to determine the frequency. The
console processor 22 (FIG. 1) or other suitable console circuitry can be
employed to perform this determination functionality. Of course, the data
can take any one of a variety of formats and configurations to enable
information relating to the pulse signal to be received by the console or
other suitable component of the system. In certain embodiments, the
console 20, the sensor unit 50, or other suitable component of the system
10 can include the necessary circuitry to synchronize with the signal
produced by the stylet 100, as described herein.

[0161]The transmitter 1138 can transmit, and the receiver 1142 receive,
the above-referenced data in any number of ways, but in one
implementation the transmitter transmits via infrared ("IR") or
radiofrequency ("RF") wavelengths for receipt by the receiver. As such,
for example, the transmitter 1138 and receiver 1142 can be configured as
an IR LED/detector pair in the first case, or as an antenna pair in the
second case. Note that other types of transmitter/receiver configurations
can be included to perform the intended functionality described herein.
Other forms of electromagnetic radiation can be employed to transmit
data, including visible light in one embodiment.

[0162]In one embodiment, the timer circuit of the untethered stylet
control module is configured to be adjustable such that the pulse
frequency can be selected from a plurality of predetermined frequency
options. Such functionality may assist in the case where interference
exists on one or more of the predetermined frequencies, where different
stylets are used successively by the same system, or where multiple
systems are used simultaneously in close proximity to one another. In
such a configuration, a selector switch may be included on the control
module housing 102A, the console 20, and/or other suitable system
component. The above or other suitable synchronization scheme can be used
to coordinate the selected pulse frequency to be transmitted and received
between the stylet control module and the console.

[0163]In another implementation, the stylet control module/console
automatically switches to one of a plurality of possible pulse
frequencies for use in driving the coil assembly. In this latter
implementation, the console can be configured to successively scan the
plurality of possible frequencies and perform frequency identification
functions, including phase locking, to identify the frequency on which
the stylet control module timer circuit is producing the electrical pulse
signal, thus enabling synchronization of the console therewith.

[0164]FIG. 42 shows an example of the above synchronization
implementation, according to one embodiment. As shown, a transmitter such
as an antenna 1152 is included with the stylet control module 102 and is
configured to emit radiofrequency ("RF") or other suitable signals. A
receiver such as an antenna 1161 is included with the console 20 of the
system 10 to receive signals emitted by the stylet control module antenna
1152. The console further includes various components for processing
signals received by the antenna 1161, including a mixer 1163, an
oscillator 1165, a low pass filter 1166, an analog-to-digital converter
("ADC") 1167, and a digital signal processor ("DSP") 1168.

[0165]During operation of the system 10, the stylet antenna 102B of the
stylet control module 102 emits an RF or other suitable signal (e.g.,
infrared ("IR")) that provides data relating to the frequency of the
pulse signal. The RF signal is received by the console antenna 1161. The
mixer 1163 combines the signal received by the antenna 1161 with a
predetermined signal generated by the oscillator 1165, which combined
signal is then filtered through the low pass filter 1166 to remove any
extraneous signals. The filtered and combined signal is passed through
the ADC 1167, then analyzed by the DSP 1168 to determine whether the two
signals forming the combined signal match. If so, phase shifting of the
signals will be performed by the DSP and/or oscillator 1165 to lock the
signals in phase.

[0166]If the signals do not match, the above process is repeated with a
new signal having a different frequency being produced by the oscillator
1165 until the signal. The above process is iteratively repeated until
the signal from the oscillator matches in frequency the signal emitted by
the stylet control module antenna 1152 and subsequently received by the
console antenna 1161. Thus, the oscillator 1165 in one embodiment is
capable of cycling through a plurality of pre-set signal frequencies in
attempting to match the emitted signal of the stylet control module
antenna 1152. In another embodiment, the oscillator can cycle through a
range of frequencies in attempting to match the emitted signal. As noted
before, once the proper signal frequency is determined by the console 20,
phase shifting as needed can be conducted to complete synchronization
between the stylet 100 and the console 20, thus enabling the console to
track the distal end of the stylet 100.

[0167]It is understood that the above is merely one example of
synchronizing the pulse signal produced by the stylet coil assembly with
the console and that other implementations can be employed to link the
frequency between the stylet coil assembly and console or other component
of the system.

[0168]In another embodiment, it is appreciated that the
transmitter/receiver configuration can be reversed such that the
transmitter is included with the console and directs information
regarding the frequency of the pulse signal to the stylet control module,
which receives the information via a receiver included therein. In yet
another embodiment, both the stylet and the console are manufactured to
operate with a pre-set pulse signal frequency, requiring no subsequent
synchronization therebetween. These and other possible configurations are
therefore contemplated. Generally, it should be understood that the pulse
circuitry and timer circuit of the stylet control module, together with
the processor of the console 20, can be configured in one or more of a
variety of ways to achieve above-described functionality. For instance,
the processor 22 of the console 20 can be included in the sensor unit 50
(FIG. 1, 38) such that synchronization operations on behalf of the system
10 are performed by the sensor. Or, in another embodiment the stylet
functionality is incorporated into the catheter itself and no removable
stylet is employed.

[0169]Reference is again made to FIG. 38, which shows disposal of the
untethered stylet 100 substantially within a lumen in the catheter 72
such that the proximal portion thereof, including the control module 102,
extends proximally beyond the catheter lumen, the hub 74A and a selected
one of the extension legs 74B. So disposed within a lumen of the
catheter, the coil assembly 1106 proximate the distal end 100B of the
stylet 100 is substantially co-terminal with the distal catheter end 76A
such that detection by the TLS of the stylet coil assembly
correspondingly indicates the location of the catheter distal end.

[0170]The TLS sensor unit 50 is employed by the system 10 during TLS
operation to detect the electromagnetic field produced by the coil
assembly 1106 of the stylet 100. As seen in FIG. 38, the TLS sensor unit
50 is placed on the chest of the patient during catheter insertion. The
TLS sensor unit 50 is placed on the chest of the patient in a
predetermined location, such as through the use of external body
landmarks, to enable the field of the stylet coil assembly 1106, disposed
in the catheter 72 as described above, to be detected during catheter
transit through the patient vasculature. Again, as the coil assembly 1106
is substantially co-terminal with the distal end 76A of the catheter 72
(FIG. 38), detection by the TLS sensor 50 of the field produced by the
coil assembly provides information to the clinician as to the position
and orientation of the catheter distal end 76A during its transit.

[0171]In greater detail, the TLS sensor unit 50 is operably connected to
the console 20 of the system 10 via one or more of the ports 52, as shown
in FIG. 1. Note that other connection schemes between the TLS sensor and
the system console can also be used without limitation. As just
described, the coil assembly 1106 is employed in the stylet 100 to enable
the position of the catheter distal end 76A (FIG. 38) to be observable
relative to the TLS sensor unit 50 placed on the patient's chest.
Detection by the TLS sensor unit 50 of the stylet coil assembly 1106 is
graphically displayed on the display 30 of the console 20 during TLS
mode, represented in FIGS. 6-8C, for example. In this way, a clinician
placing the catheter is able to generally determine the location of the
catheter distal end 76A within the patient vasculature relative to the
TLS sensor unit 50 and detect when catheter malposition, such as
advancement of the catheter along an undesired vein, is occurring. It
should be appreciated that in one embodiment the positions of the
radiating element and the sensor can be reversed such that remotely
powered sensor is included with the stylet for detecting a field produced
by the radiating element positioned external to the body of the patient.

[0172]As mentioned further above, note that the system 10 in one
embodiment can include additional functionality wherein determination of
the proximity of the catheter distal tip 76A relative to a sin
θ-atrial ("SA") or other electrical impulse-emitting node of the
heart of the patient 70 can be determined, thus providing enhanced
ability to accurately place the catheter distal tip in a desired location
proximate the node. Also referred to as "ECG" or "ECG-based tip
confirmation," this third modality of the system can enable detection of
ECG signals from the SA node in order to place the catheter distal tip in
a desired location within the patient vasculature. Note that any
functionality of an ECG sensor included with the stylet may be
incorporated with the stylet control module to provide a wireless pathway
for transmitting ECG sensor data from the stylet ECG sensor to the system
console, the TLS sensor, or other system component in conjunction with
catheter placement procedures. Such functionality can be in addition to
the inclusion of a radiating element, such as the coil assembly spoken of
herein. Note further that, in one embodiment, the control module housing
can further serve as a handle to assist in manipulating the catheter
and/or stylet during intravascular advancement.

[0173]The untethered stylet associated with the system as described
immediately above herein allows for simple management of the sterile
field that is established about the insertion site 73 of the patient 70
(FIG. 38) during the catheter placement procedure by eliminating wires
interconnecting the stylet and the console that would have to penetrate
through the sterile field. FIGS. 43A-44 provide yet another solution for
operably interconnecting a radiating element included with a stylet or
other suitable device through the sterile field of the patient without
compromising the sterility of the field, according to one embodiment. In
particular the proximal end 100A of the stylet 100, instead of including
a control module 102, rather includes a tether connector 2132 configured
for operably connecting to a corresponding sensor unit connector 2156
disposed on the sensor unit 50, as shown in FIG. 43A. The tether
connector 2132 in the present embodiment is operably connected to the
distal portion of the stylet 100 via a tether 2134. Note that, though
configured similarly to the tether connector 132 and fin connector 156
shown in FIGS. 14A-14C in connection with the ECG modality of the
catheter placement system 10 as described further above, the tether
connector 2132 and sensor connector 2156 that enable operable connection
of the radiating element with the sensor unit 50 can be configured in
other ways. As such, the discussion here is understood to describe merely
one possible example of operable interconnection of a radiating element
of a stylet or medical device with a sensor unit or other suitable
component of a catheter placement system. Many other types of operable
interconnection can be employed, as appreciated by one skilled in the
art.

[0174]FIG. 43B shows the slide-on manner of connection of the tether
connector 2132 with the sensor connector 2156 of the sensor unit 50. FIG.
44 shows a cross sectional view of the interconnection of the tether
connector 2132 with the sensor connector 2156, wherein a channel 2172 of
the tether connector includes a piercing element, such as a pin contact
2170, which extends into the channel. The drape 174 that covers the
sensor unit 50 when the sensor unit is placed on the chest or other
portion of the body of the patient is interposed between the tether
connector 2132 and the sensor connector 2156 when the tether connector is
slid on the sensor connector such that the pin contact 2170 pierces the
drape, extends past a centering cone 2164 and through a hole 2162 defined
in the sensor connector. Once the tether connector 2132 is seated on the
sensor connector 2156, the pin contact 2170, which is electrically
bifurcated, physically contacts two contacts 2168 disposed in the sensor
connector so as to enable a suitable closed circuit to be established
therebetween. In this way, the radiating element, e.g., the coil 1106, of
the stylet 100 is operably connected via the tether 2134 and connectors
2132/2156 with the necessary driving circuitry for driving the coil,
which circuitry can be located in the sensor unit 50, console 20, etc.

[0175]Furthermore, the interconnection of the tether connector 2132 with
the sensor connector 2156 is established through the drape 174 without
compromising the barrier provided by the drape for establishing sterility
about the catheter insertion site 73 (FIG. 38), similar to previous
embodiments discussed further above in connection with the ECG modality
of the catheter placement system 10. Indeed, the tether connector 2132
desirably covers and isolates the drape breach made by the piercing pin
contact 2170. Again, other types of through-drape connective schemes can
be employed for operably connecting the radiating element with the sensor
unit without compromising the sterile field.

[0176]Thus, in one embodiment, a method for operably connecting a
radiating element with a sensor unit includes positioning the sensor unit
on the patient, placing the sterile barrier over the sensor unit, and
operably connecting the radiating element to the sensor unit by
penetrating the sterile barrier.

[0177]Although the embodiments described herein relate to a particular
configuration of a catheter, such as a PICC or CVC, such embodiments are
merely exemplary. Accordingly, the principles of the present invention
can be extended to catheters of many different configurations and
designs.

[0178]Embodiments of the invention may be embodied in other specific forms
without departing from the spirit of the present disclosure. The
described embodiments are to be considered in all respects only as
illustrative, not restrictive. The scope of the embodiments is,
therefore, indicated by the appended claims rather than by the foregoing
description. All changes that come within the meaning and range of
equivalency of the claims are to be embraced within their scope.

Patent applications by Eddie K. Burnside, Grantsville, UT US

Patent applications by Shayne Messerly, Kaysville, UT US

Patent applications by C. R. Bard, Inc.

Patent applications in class With means for determining position of a device placed within a body

Patent applications in all subclasses With means for determining position of a device placed within a body